A-1 Miller's Performance Enterprises "Old-School" Automotive Tips and Tricks

Educating and Inspiring "Old School" Automotive Enthusiasts. Where Science and Common Sense Come Together for Improved Engine and Vehicle Performance | Click or tap HERE or HERE to refresh or reload this web page to see any changes. If you have any questions please contact A-1 Miller's Performance Enterprises at 1-573-881-7229 (cell/text) | E-mail: pullingtractor@aol.com. FYI - The reason I have never made any YouTube videos is because I stutter. I'm afraid the viewer's mockery and negative comments would take all the educational benefits and fun out of them.

Identification of the Small Block Chevy V8 Engines -

The Small-Block Chevy (SBC) engine evolved significantly over its lifetime. Originally, the 1955-1985 engines featured a two-piece rear main seal, a driver's-side dipstick, and an oil pan with a thin front seal. By 1986, GM transitioned to a one-piece rear main seal with a passenger-side oil dipstick and block-mounted starter for manual transmissions.

The Rear Main Seal Evolution:

The Oil Dipstick Evolution. The location of the SBC dipstick serves as a quick visual indicator of the engine's era and rear main seal design:

The year of manufacture of virtually every vehicle is embossed on the front, rear and side marker light lenses. But only if the original lenses are on the vehicle.

The old school Chevy V8 carbureted "smog" engines can be very powerful when certain deletions and simple modifications are made. These engines became notorious during the EPA-regulated smog era. Anyway, the best way to get more power is...
  • Remove all the smog sensors and cap-off their vacuum ports on the carburetor, and plug the threaded ports in the intake manifold and thermostat housing with metal NPT plugs.
  • Remove the air pump and lines, and plug the holes in the exhaust manifolds.
  • Connect the vacuum advance canister to a full manifold vacuum port (located below the throttle plates; draws vacuum full time) instead of ported vacuum (located with the throttle plates; only draws vacuum when the engine is revved up above idle).
  • Install lightweight springs for a lubricated mechanical advance in the distributor.
  • Install a low resistance bronze rotor distributor bushing from Speedway Motors (part # 122222DUI) or MSD (part # 8412) for a stronger spark.
  • Install copper core/non-resistor spark plugs for a stronger spark.
  • And as an option, install higher compression cylinder heads and/or flat top pistons.

Doing all of the above will turn the engine into a screamer! I proved this many times with my customer's engines. It may have ran like a dream before, but with these modifications, it'll run beyond your wildest dreams!

A ported vacuum advance is an EPA required emissions thing. Not recommended because the engine will idle poorly, especially with an automatic transmission when in gear. Full manifold vacuum works much better. The engine will idle better and provide more power with better fuel economy.

At idle, the timing should be fully advanced by the vacuum advance canister at all times. This is why it's recommended that the vacuum hose be disconnected from the vacuum advance and plugged before setting the initial timing with a timing light. Then with the hose reconnected, as soon as the engine revs up, vacuum will drop, and the mechanical timing weights (with lightweight springs) in the distributor will take over, maintaining full timing advance so the engine will continue to produce full power.

Remove the Valve from The Heat Riser for Better Engine Performance -

A heat riser is an automotive exhaust component or valve designed to direct hot exhaust gases through the intake manifold to speed up engine warm-up during cold weather.

How It Works:

Common Issues:

Deletion and Solution:

Nostalgic Memorabilia -

I remember during the 1970s-early '80s when gas was cheap and life was fun, long before the Internet, a lot of young people would street race their hot rods on the main drag in town. When at an intersection with a red light, another hot rodder would pull up next to your car, look it over front to end, then look at you, and then he'd turn his head straight ahead, and shook his head up and down, indicating to you: "Let's Go!" And the race was on as soon as the light turned green. Ahhh, the good ole days.

Back in the day (early 1980s and earlier), gasoline at most filling service gas stations for various [automotive and other types of] engines were for the following compression ratios:

Actually, ALL gasoline in the early days contained lead (Tetraethyllead) to boost octane and protect soft cast iron valve seats from wearing. I'd also like to share this old gas station joke: Car owner that just pulled up to the pump at a full service gas station says to the gas station attendant: "Fill 'er up... Ethyl!" Gas station attendant: "I'll fill up your car, but don't call me Ethel."

FYI - Until the late 1960s, certain Chevrolet small block muscle car engines had a compression ratio as high as 11.25:1, and a certain Chevrolet 427 big block muscle car engine had a compression ratio of 14:1! (That was the good ol' days of hot rodding!) In fact, back then, Chevrolet made the only naturally aspirated engine out of the top three American (GM, Ford and MOPAR) car manufacturers that had the highest compression ratio.

Muscle cars, raised white lettering on 70s, 60s or 50s rear tires, air shocks, glasspack mufflers, Cragar SS's or SST's, 4 barrel carburetors and low-priced gas. Cruising and racing the main drag in town with friends and associates on the weekends. Dang, the good ole days! These were the best of times, and we didn't even know it. Nowadays, it's only car show events.

Gasoline octane ratings have evolved from simple, low-octane fuels in the early 1900s to today's standardized three-grade system. Octane measures a fuel's ability to resist engine knock or premature detonation.

I found that when welding a nut to a broken-off bolt to extract the stud, it's better to use a shallow jam nut instead of an ordinary deep nut. Because the bead of weld will be more secure to the stud with a jam nut than with an ordinary nut. This makes the weld stronger, and hopefully, the broken off bolt can be easily removed.

Sometimes using just one air filter on a hort rod is restrictive for the amount of air the engine requires. Therefore, many ho rodders stack two air filters, one stacked on top of other, to increase the air flow. Then a longer threaded stud will need to be used.

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Click here to contact A-1 Miller's Performance Enterprises to place an order, send your parts for repairing, and/or for FREE professional and honest technical customer service assistance and support and payment options. Please contact A-1 Miller's if you need a part or parts, or service(s) performed that's not listed or mentioned in this website.
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NOTE: To clean the foam wrap/pre-filter, use brake parts cleaner, electrical/electronic contact cleaner, cleaning solvent or paint thinner (these leave behind no oily residue) and 150± P.S.I. compressed air with an air blow gun nozzle, allow to thoroughly dry, but do not add oil in an attempt to trap the dust and dirt. Oil is not recommended because some of the oil could be drawn into the paper element while the engine is running, partially clogging it.
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NOTE: To clean the foam wrap/pre-filter, use brake parts cleaner, electrical/electronic contact cleaner, cleaning solvent or paint thinner (these leave behind no oily residue) and 150± P.S.I. compressed air with an air blow gun nozzle, allow to thoroughly dry, but do not add oil in an attempt to trap the dust and dirt. Oil is not recommended because some of the oil could be drawn into the paper element while the engine is running, partially clogging it.
Pleated Air Filter Elements and Reticulated Foam Wraps/Pre-Filters. Non-restricting flame retardant filter. Performance engineered for increased breathing. Can be used with one or two 4-barrel carburetors on a mini rod pulling vehicles, hot rods, etc., with an automotive engine. Air filter: Kohler 24 083 09-S; John Deere GY20576. Foam Wrap/Pre-Filter: Kohler 24 083 02-S. Air filter element dimensions (±): 7" O.D. x 5-1/2" I.D. x 3" overall height.
  • High quality aftermarket air filter. Same quality as OEM. $11.00 each, plus shipping & handling.
    • High quality aftermarket foam wrap/pre-filter. $3.50 each, plus shipping & handling.
  • OEM Kohler air filter. $20.05 each, plus shipping & handling.
    • OEM Kohler foam wrap/pre-filter. $4.55 each, plus shipping & handling.

NOTE: To clean the foam wrap/pre-filter, use brake parts cleaner, electrical/electronic contact cleaner, cleaning solvent or paint thinner (these leave behind no oily residue) and 150± P.S.I. compressed air with an air blow gun nozzle, allow to thoroughly dry, but do not add oil in an attempt to trap the dust and dirt. Oil is not recommended because some of the oil could be drawn into the paper element while the engine is running, partially clogging it.
Pleated Air Filter Elements and Reticulated Foam Wraps/Pre-Filters. Non-restricting flame retardant filter. Performance engineered for increased breathing. Can be used with one or two 4-barrel carburetors on a mini rod pulling vehicles, hot rods, etc., with an automotive engine. Air filter: Kohler 45 083 02-S; Cub Cadet 759-3359. Foam Wrap/Pre-Filter: Kohler 45 083 01-S. Air filter element dimensions (±): 6" O.D. x 4-11/16" I.D. x 3" overall height.
  • High quality aftermarket air filter. Same quality as OEM. $9.00 each, plus shipping & handling.
    • High quality aftermarket foam wrap/pre-filter. $3.50 each, plus shipping & handling.
  • OEM Kohler air filter. $17.00 each, plus shipping & handling.
    • OEM Kohler foam wrap/pre-filter. $3.75 each, plus shipping & handling.

NOTE: To clean the foam wrap/pre-filter, use brake parts cleaner, electrical/electronic contact cleaner, cleaning solvent or paint thinner (these leave behind no oily residue) and 150± P.S.I. compressed air with an air blow gun nozzle, allow to thoroughly dry, but do not add oil in an attempt to trap the dust and dirt. Oil is not recommended because some of the oil could be drawn into the paper element while the engine is running, partially clogging it.
Pleated Air Filter Elements and Reticulated Foam Wraps/Pre-Filters. Non-restricting flame retardant filter. Performance engineered for increased breathing. Can be used with one or two 4-barrel carburetors on a mini rod pulling vehicles, hot rods, etc., with an automotive engine. Air filter: Kohler 277138-S. Foam Wrap/Pre-Filter: Kohler 277593-S. Air filter element dimensions (±): 6" O.D. x 4-3/4" I.D. x 4" overall height.
  • High quality aftermarket air filter. Same quality as OEM. $12.00 each, plus shipping & handling.
    • High quality aftermarket foam wrap/pre-filter. $5.00 each, plus shipping & handling.
  • OEM Kohler air filter. $20.70 each, plus shipping & handling.
    • OEM Kohler foam wrap/pre-filter. $16.10 each, plus shipping & handling.

NOTE: To clean the foam wrap/pre-filter, use brake parts cleaner, electrical/electronic contact cleaner, cleaning solvent or paint thinner (these leave behind no oily residue) and 150± P.S.I. compressed air with an air blow gun nozzle, allow to thoroughly dry, but do not add oil in an attempt to trap the dust and dirt. Oil is not recommended because some of the oil could be drawn into the paper element while the engine is running, partially clogging it.

1" and 2" Carburetor Spacers for Old School Automotive V8 Engines -

On most old school automotive V8 engines with a 4-barrel carburetor and stock intake manifold, a 1" carburetor spacer generally boosts torque and top-end power while avoiding low-end losses. A 2" spacer requires specific race cams and higher RPM ranges to see gains, and can actually lose mid-range torque on a street engine due to excessive plenum volume.

How They Work:

Key Differences at a Glance:
1" Spacer
  • Best For Street/strip builds, mild daily drivers, dual-plane intakes.
  • Power Band Broadens torque and increases mid-to-high RPM power without major low-end compromises.
  • Plenum Volume Ideal for smaller to medium 350ci SBCs.
  • Hood Clearance Fits under most standard SBC muscle car hoods.
2" Spacer
  • High-RPM racing applications, large-displacement SBCs, single-plane intakes.
  • Maximizes top-end peak power, but can sacrifice "low-end torque".
  • Massively increases plenum volume; often drops mid-range torque on street setups.
  • Typically requires cowl hoods or race setups.

Which One Should You Choose?

Carburetor Spacer vs Dual-Plane Intake Manifold vs High-Rise Intake Manifold -

Carburetor spacers, dual-plane intake manifolds, and high-rise intake manifolds all alter the volume, velocity, and delivery path of the air-fuel mixture to an automotive engine. The best choice depends entirely on the engine's operating RPM, intended use (street vs. track), and under-hood clearance.

Carburetor Spacer:

Dual-Plane Intake Manifold:

High-Rise Intake Manifold:

How to Choose:

FYI - The automotive V8 high rise intake manifold and Chrysler's Slant Six engine (with the longer intake manifold runners) were designed to atomize the fuel better so the engine will produce more power at higher RPM and get better fuel mileage at any RPM. If anyone tells you differently about the Chrysler slant six engine, then they are wrong! These are the ONLY reasons Chrysler made the slant six engine, designed it the way they did and it works!

Exhaust Manifold or Header Pipe Mounting Gaskets VS Using Just Silicone Sealant Alone - Which Works Best?

Personally, whenever we install exhaust manifolds or header pipes on an engine, we don't use gaskets. Instead, we use RTV clear silicone sealant because silicone will not burn due to normal or extreme exhaust heat. (Silicone can withstand up to 5,000º F.) Anyway, gaskets always compress or "squeeze down" where the fastening bolts are, causing the cast iron manifold to flex a few thousandths of an inch or thinner steel header flanges to bend more than a few thousandths of an inch where the mounting bolts are. When metal is compressed, the uncompressed area that's between the bolts will allow the gasket(s) to leak and eventually burn out. Also, before we install the manifolds or headers on an engine, we use a long, wide flat file to make sure the mounting flanges on the manifolds or headers are perfectly flat. Using silicone and the elimination of gaskets will allow the manifolds or header flanges to be mounted flat against the cylinder heads, creating absolute metal-to-metal contact, which also keep the mounting bolts securely tight. The bolts will not loosen under any circumstances. Plus, the silicone fills in the imperfections between the two metals, eliminating any leaks. By the way - it's best to use Clear RTV Silicone Adhesive Sealant for three reasons: Gaskets don't always seal the irregularities between mating metals, especially thin metal covers; being it's an adhesive, it bonds parts together, forming a leak-proof seal; and being it's clear, it makes for a clean and professional-looking repair job. When applied sparingly, it can't be easily seen or noticed between the parts. Also, engine heat has very little effect on silicone rubber. It can withstand up to 2,500 degrees heat.

On a small-block Chevy V8, to provide more lubrication to the timing chain and sprockets, drill a 1/32" or 3/64" hole through one of the front lifter oil galley plugs, which are located directly behind the upper timing sprocket or gear.

Crucial Details and Best Practices:

If the engine's thermostat doesn't already have this, drill a 3/32" hole through the thermostat plate area. This will allow any air that's trapped in the block to be pushed out, and it'll allow coolant to drain into the block to prevent air pockets, which could result in premature overheating. By drilling the 3/32" hole, this will allow any air out of the block, especially when filling the radiator/engine with coolant, and this hole will also help the engine warm up faster by allowing the coolant make contact with the coil spring in the thermostat.

The reason the blades on automotive radiator fans are offset is to reduce the "chopping" sound at higher rpms. Otherwise, they'd sound like an airplane going down the road.

The outlet/hot side heater hose is most likely to burst close to the engine block or water pump because this is the hottest point. To prevent this from happening, replace the OEM 1 ply heater hose with a heavy duty 2 ply reinforced hose and avoid any sharp bends to prevent from having a blow-out later. Because sharp bends weakens the hose material by placing stress on the hose. Also, install a cable-operated shut-off valve in the outlet hose that can be operated from inside the vehicle. The shut-off valve saves wear and tear on the heater hoses and heater core during warm weather and allows the a/c to produce colder air.

I think most older vehicles don't need to be converted to disc brakes. Because drum brakes will work just fine as long as they're in good condition. The only exception is when replacement drum brakes and/or parts are not available. Besides, brakes only work as good as the person who use them.

Ignition points should never be cleaned with sandpaper or emery cloth. Doing this will leave grit between the contacts, which will cause a poor connection. Instead, a thin, steel points file should always be used. This tool will leave the contacts clean for a good connection.

When regrinding a valve face, always true-up the end of the valve stem. Because in an OHV cylinder head, a rounded or unevenly worn valve stem tip can cause the rocker arm to slip, slide sideways, or track improperly.

Why It Happens:

What Else to Check. If a rocker arm is slipping to one side, a rounded valve tip might be a symptom or a contributing factor, but look for these related root causes:

How to get more power out of an old school Chevy V6 or small block Chevy V8 smog engine...

Small Block Chevy (SBC) Distributor Gear Alignment Details -

I always rebuild OEM GM HEI distributors. I disassemble, clean, lubricate the shaft, and drill 2 holes through the housing so the bushings will receive crankcase oil. Then I replace the OEM carbon bushing with a new MSD bronze bushing in the center of the distributor cap for a stronger spark and to prevent from melting the cap. i also install lightweight springs for the mechanical advance so the engine will produce more power. The springs in an old sbc points distributor will fit the HEI distributor. They're lightweight, too.

What's the Difference Between the Small Block Chevy 305 and 350 Distributor Vacuum Advance?

Understanding Vacuum Advance and Why It's Needed: While Small Block Chevy (SBC) 305 and 350 distributors are often physically interchangeable, their vacuum advance units typically differ in calibration to match distinct engine characteristics, such as compression ratios and timing requirements. A 305 vacuum advance is often tuned for higher emissions-era vacuum signals, whereas a 350 vacuum advance is tuned for higher performance and broader timing curves.

Key Differences and Considerations:

Connecting the vacuum advance to the [part time] throttle vacuum (often called "ported" or "timed" vacuum) is to dynamically adjust ignition timing based on engine load. It improves throttle response, increases fuel efficiency during cruising, and prevents the engine from overheating.

Here is a breakdown of why this connection is important:

1. The Core Purpose: Load-Based Timing

An engine requires different amounts of spark advance depending on how hard it is working (load).

At cruising speeds: The engine is under light load, taking in less air, and the fuel mixture burns relatively slowly. The vacuum advance uses the high vacuum signal to advance the timing, ensuring the fuel burns completely before the exhaust valve opens. This drastically improves fuel economy, increases engine power and lowers emissions.

At full throttle: The engine is under a heavy load and cylinder pressure spikes. The vacuum drops significantly, and the vacuum advance disengages. This prevents dangerous pre-ignition or engine "knock" (detonation).

2. The Mechanics: of Ported vs. Manifold Vacuum

There are two ways to connect the vacuum advance on a carburetor, and their purpose dictates how the car behaves:

Ported Vacuum (Throttle Body): The vacuum port is located just above the throttle plates. At idle, the throttle plates block this port, so there is no vacuum going to the vacuum advance. As the throttle slightly opens, air speeds up past the port, creating a strong vacuum signal that immediately advances the timing for a smooth transition. This was standard on many factory vehicles from the emissions era onward.

Manifold Vacuum: The port is part of the intake manifold, meaning it has high vacuum the moment the engine is running. This advances the timing at idle, which yields a smoother and stronger idle. Many performance enthusiasts and restorers prefer connecting the vacuum advance to manifold vacuum for a more efficient burn.

Summary of Benefits

Connecting the vacuum advance to a full-time manifold vacuum port ensures the ignition timing stays stable at idle , while still providing extra advance during part-throttle acceleration for better fuel economy and drivability.

The main functional differences and advantages of using ported vacuum depend on how you drive and tune the engine.

The Core Advantage: Idle Stability

No Timing at Idle: Ported vacuum is taken from above the throttle plates, meaning there is virtually no vacuum signal when your foot is off the gas.

Stable Base Timing: By preventing vacuum advance at idle, the engine relies solely on its base (initial) timing. This prevents erratic idle surges, especially on older engines or vehicles with aggressive, long duration camshafts that already have low, unstable manifold vacuum.

Part-Throttle Performance and Economy

Timing on Demand: As soon as you step on the throttle and open the plates, the vacuum port is exposed to the engine's vacuum, pulling timing in.

Efficiency: This extra timing advance at light-load cruising (when the throttle is just barely cracked) allows for a more complete fuel burn. This translates to crisper throttle response and better gas mileage.

Ported vs. Manifold Vacuum

While ported vacuum is the standard for street-driven carbureted and older vehicles, understanding the trade-off with manifold vacuum can help you tune your specific setup:

Ported Vacuum Manifold Vacuum

Tuning and Best Practices

If you are deciding which to use, always check the distributor's technical specifications, as most aftermarket units (such as those from MSD or Summit Racing) are specifically engineered to run on ported vacuum. To avoid engine hesitation or pinging under acceleration, you can utilize an adjustable vacuum advance canister to dial-in exactly how much timing the engine has at part throttle.

Additionally, the 305's distributor originally comes with very stiff mechanical flyweight advance springs that allow full timing advance at around 4,000 RPM. The 350's distributor originally comes with weaker mechanical flyweight advance springs that allow full timing advance at around 2.500 RPM. So in order for the 305 to produce more power at lower RPMs, install the weaker springs designed for the 350.

When using a Chevy 305 engine with its original distributor, to make it produce lots more power, replace the stiff mechanical timing advance springs in the distributor with lightweight springs out of a 283, 307, 327, 350 or 400 distributor. The 305's stiff springs fully advances the total timing of 36° BTDC at around 4,000 RPM, and the other SBC engine's lightweight springs fully advance the total timing of 36° BTDC at around 2,500 RPM. I did this with several stock 305s, and this simple, easy trick made a world of difference in the increase of power. Also, at idle, the timing should be fully advanced by the vacuum advance canister at all times. This is why it's recommended that the vacuum hose be disconnected from the vacuum advance before setting the initial timing with a timing light. With the hose reconnected, as soon as the engine revs up, vacuum will drop, and the mechanical timing weights (with lightweight springs) will take over, maintaining full timing advance.

Installing light-weight mechanical advance springs and a properly adjusted vacuum advance canister (like those often used in performance-tuned 350 setups) will likely make a 305 Small Block Chevy (SBC) feel more responsive and produce better part-throttle power and efficiency, though it may not increase peak horsepower. Stock 305 distributors were often set up conservatively for emissions and fuel economy, with heavy mechanical advance springs that allow the timing to advance slowly.

Here is how these changes affect performance:

For a typical Small Block Chevy (SBC) V8 (e.g., 350), and depending on the compression ratio, set initial timing at 8-12° Before Top Dead Center (BTDC) at idle and total advance to 34-36° at 2,500-3,000 RPM (with vacuum advance disconnected). Optimal timing varies based on cam, cylinder head design, and fuel, with performance engines often preferring higher initial timing.

Key Timing Specifications:

Steps for Setting Timing

On automotive engine distributors, lightweight springs are used in a mechanical (centrifugal) distributor advance to allow the ignition timing to advance faster at lower engine RPMs. These springs allow the centrifugal weights to swing outward sooner, reaching "total timing" (maximum advance) at a lower engine speed, which is used to improve throttle response and performance in many engines.

Key Reasons for Using Lightweight Springs:

Medium springs are used in mechanical timing advance mechanisms to control the rate of spark advance, ensuring it matches the engine's RPM without advancing too quickly, which can cause spark knock or "pinging sound". They act as a middle ground between light springs (fast advance) and heavy springs (slow advance), offering a tailored, progressive advance curve.Key Reasons for Using Medium Springs:

Preventing Premature Advance: Lighter springs can cause the timing to advance too early (e.g., at 800 RPM or lower), leading to engine misfire or detonation. Medium springs hold the weights back until a higher, more appropriate RPM.Creating a Progressive Curve: Often combined with a lighter spring, medium springs allow the timing to start advancing quickly but slow down the rate of advance at higher RPMs, reaching "total timing" at the desired engine speed, typically around 3,000 RPM.

Stability at Idle: They ensure the mechanical advance does not activate during idle or low-speed operation, providing better timing stability and preventing an unsteady idle.Balancing Performance: They provide a balanced approach, allowing for quicker advance than heavy springs for performance, without the risks associated with excessively fast "light spring" curves.

Heavy springs in a mechanical timing advance system (centrifugal advance) are used to slow down the rate of advance, delaying when the maximum ignition advance is achieved until higher RPMs. Stiffer springs fight the centrifugal force of the distributor weights more effectively, preventing premature timing advance that can cause engine detonation or "pinging sound".

Key Reasons for Using Heavy Springs:

Delay Timing Curve: They prevent the mechanical advance from starting too early, often used to keep initial timing stable at idle.

Prevent Detonation: By preventing the timing from advancing too quickly, they protect the engine from pre-ignition/detonation, particularly under high loads.Tailor the Timing Curve: Heavier springs (or a combination of one light/one heavy) are used in "slower" tuning kits to ensure total timing occurs at higher RPMs (e.g., 3,000+ RPM) rather than too early (e.g., 1,500 RPM).Distributor Stability: Stiffer springs prevent "flutter" of the advance weights, resulting in more stable timing.In summary, light springs allow for fast advancement (suitable for racing), while heavy springs restrict that motion for a slower, controlled advance (better for street tuning).

Many high-performance automotive engine builders often weld the mechanical advance weights in place and they install a solid plate in place of the vacuum advance canister, so the ignition timing is in a "fixed" position, ensuring the total timing remains the same rather than automatically advancing with RPM. This technique is common in high-performance engines to prevent detonation and provide a consistent ignition curve.

Small-block Chevy (SBC) V8s with stock camshafts should idle at their initial/base timing setting with the vacuum advance disconnected. While full manifold vacuum is often used for cooling and idle quality, the advance canister must be disconnected and plugged while setting the base idle speed and timing.

Why the distinction matters:

Idle Timing by Transmission Type.:

Automatic Transmission:

The Challenge: Engines with A/Ts idle under "load" when the transmission is in gear, which drops engine vacuum and RPMs.

Manual Transmission:

The Challenge: Manual transmissions don't load the engine at a stop, but they require reliable, clean throttle response when engaging the clutch from a dead stop.

Step-by-Step Tuning Rule. Whether an A/T or manual, always follow these rules to tune the distributor:

  1. Disconnect and Plug: Pull the vacuum hose off the distributor advance canister and plug it with a golf tee or screw so it don't have a vacuum leak.
  2. Set Initial Timing: Rotate the distributor body so the timing mark aligns with the stock specifications (typically 8° to 12° BTDC).
  3. Set Idle Speed: Adjust the idle screw on the carburetor until it hits the target RPM (usually 600-700 RPM in gear for A/T; and 700-800 RPM for manual).Reconnect the Vacuum Advance: Reattach the vacuum hose to either a manifold or ported source, depending on the cam and heat preferences.

Setting the Ignition Timing with a Strobe Timing Light - [Return to previous paragraph, section or website]

There are 3 types of strobe timing lights, in-line/neon, analog, and digital.

In-Line/Neon Timing Light. This very old, vintage, self-powered timing lights relied solely on the electrical energy from the ignition circuit to flash.

Analog vs Digital Timing Lights - (Added 6/5/26)

Analog Timing Light -

An analog timing light uses a mechanical dial to set advance and a simple xenon strobe to illuminate timing marks, while a digital timing light uses an LCD screen, pushbuttons, and microprocessor-controlled circuitry to display RPM, advance, and voltage readouts. To use an inductive analog timing light or digital timing light, the engine can be running while connecting the clamps on the battery posts in their respective order, then connect the inductive pickup on the #1 spark plug wire. Choosing between the two depends on your budget and how often you tune the engine.

Digital Timing Light -

Which One Should You Choose?

When building a high compression engine and burning 87 octane gas with the usual timing, to lessen the possibility of pre-ignition, which causes detonation and pinging, chamfer and smooth the top edge and valve reliefs of each piston and smooth out the combustion chamber in the heads. I've done this many times and it works great. Giving the top sharp, square edge of pistons a beveled or chamfered smooth angle, and smoothing out the combustion chamber of a high-compression engine will lessen the chance of pre-ignition, which causes detonation and pinging.

Cast iron is more prone to pre-ignition than aluminum because it has lower thermal conductivity and higher heat retention, which creates localized hot spots in the combustion chamber.

Why Cast Iron Retains More Heat:

How Aluminum Solves This:

Chamfering or Radiusing the Sharp, Square Edges on Pistons and/or in Cylinder Heads Will Significantly Lessen the Chance of Pre-ignition and Detonation.

In a high-compression engine, minimizing thin protrusions is a critical safety measure because of how heat transfers within the combustion chamber. Chamfering the top edges of the pistons and smoothing out the combustion chamber significantly reduces the chances of both pre-ignition and detonation. In a high-compression engine, these modifications—often referred to as radiusing or deburring—target the primary mechanical catalysts for abnormal combustion. However, it is crucial to understand that they affect pre-ignition and detonation in two entirely different ways.

1. How it Eliminates Pre-Ignition (Preventing Hot Spots). Pre-ignition happens when the air-fuel mixture is ignited before the spark plug fires.

2. How it Reduces Detonation (Improving Flame Travel & Quench). Detonation occurs after the spark plug fires, when the remaining unburnt "end-gas" in the far corners of the chamber spontaneously explodes due to extreme heat and pressure.

Why Chamfering or Radiusing Edges Prevents Pre-Ignition:

Where to Focus When Chamfering or Radiusing:

How to Chamfer or Radius the Top Edge of a Piston:

Pre-Ignition occurs more frequently and will cause more damage to the pistons in a high-compression engine when it is placed under a heavy load. Pre-ignition is a dangerous engine problem where the air and fuel mixture inside the cylinder ignites before the spark plug fires. Pre-ignition happens when a hot spot inside the combustion chamber acts like a glow plug (hot spot) and sets off the fuel too early during the compression stroke.

Common causes include:

Effects and Damage:

Pre-Ignition vs. Detonation (Knock):

People often confuse pre-ignition with engine knock or detonation, but they are different:

Why Heavy Loads Increases Pre-Ignition:

Pre-Ignition vs. Detonation (Knock)

Engine detonation is the uncontrolled, explosive ignition of the remaining fuel-air mixture in the combustion chamber after the spark plug has fired.

What Causes Detonation?

Signs and Effects:

Engine pinging is a metallic rattling or knocking sound caused when the air-fuel mixture in an engine cylinder ignites abnormally instead of burning smoothly from the spark plug.

What Causes Engine Pinging?

Common Signs:

Both risks go up under heavy loads and high compression, which is why high-performance engines require higher-octane fuel and precise tuning to control cylinder temperatures. A vehicle with a high-compression engine (above 9.3:1 compression ratio) burning 87 octane gas is more likely to detonate and make a pinging sound at times while hauling a heavy load than while cruising steadily on the highway.

Why Hauling Causes More Pinging (Detonation):

While cruising on the highway does require steady power, it's generally much easier on a high-compression engine:

The Knock Sensor -

A defective Electronic Spark Control (ESC) module can cause the engine to lose power.

On a Chevy vehicle equipped with a 305 or 350 V8 and a computer-controlled carburetor or early fuel injection), the ESC system is responsible for monitoring engine knock via a knock sensor and constantly adjusting ignition timing. When the system fails, it severely impacts how the truck accelerates and handles loads.

How a Defective ESC Causes Power Loss

Other Common Symptoms of a Bad 1985 ESC Module

Quick Diagnostics for a '85 C10

Many owners of square-body C10s bypass a problematic ESC system entirely by swapping the factory setup out for a standard, non-ESC High-Energy Ignition (HEI) distributor with mechanical and vacuum advance weights. This bypasses the old computer-controlled spark module completely and restores steady mechanical power. The same can be done with a jumper wire with alligator clips by connecting the A and C terminals together.

Can the ESC knock sensor system get stuck in the failsafe or limp mode?

The Electronic Spark Control (ESC) system can get stuck in its failsafe mode, which causes the engine to suffer from a permanent, significant loss of power and sluggish acceleration.

On 1981–1986 GM squarebody trucks, the standalone ESC module (typically located behind the glove box) relies on a constant signal from the knock sensor. If the ESC module loses this signal or detects an internal circuit fault, it defaults to its failsafe mode, locking the system into a heavy ignition timing retard (usually pulling around 4 to 8 degrees of timing) to protect the engine from potential detonation.

Why the ESC Gets Stuck in Failsafe Mode

Unlike modern vehicles that will throw an OBD2 check engine light for a knock sensor code, a 1985 GM system—whether carbureted or early EFI—often handles this entirely via the hardware module. The module will "fail soft" and stay stuck in retard mode if:

How to Confirm It:

  1. The Tap Test: Connect a timing light, start the truck, and bring it slightly above idle (around 1,500 RPM). Have an assistant firmly tap the engine block near the knock sensor with a wrench. If the timing drops and then returns, the system is working. If the timing doesn't budge or is already excessively retarded and sluggish, the system is down.
  2. The Bypass Test: To prove the ESC is stuck in failsafe, you can temporarily bypass it. Locate the 4-pin weather-pack connector near the distributor (containing black, white, green, and brown wires). If you disconnect the ESC side and jumper the black and green wires together on the distributor side, you bypass the ESC module entirely, returning the distributor to straight mechanical/vacuum advance. If the truck suddenly regains its lost power and responsiveness, the ESC system was stuck in failsafe. (Note: Premade Plug & Play ESC Bypass Modules are commercially available for testing or permanently deleting the troublesome vintage system).

Can an Old School Engine with 10:1 Compression Ratio Run Okay on 87 Octane Gas?

Actually, an old school engine with a 10:1 static compression ratio can run very well on 87 octane gas, provided the dynamic compression ratio, camshaft design, cylinder head material, and tune are set up to handle it.

Key Factors That Decide If It Will Work

Risks of Running 87 Octane Too High:

How Can an Old School Carbureted Engine with 10:1 Compression Ratio Burn 87 Octane Gas and Not Detonate?

An older carbureted engine with a 10:1 static compression ratio can often run on 87 octane gas without detonating because of dynamic compression (which is lower than static compression), conservative ignition timing, or engine design factors that reduce cylinder pressure and heat.

Key Reasons It Can Survive on 87 Octane

The knock sensor is threaded into the engine block just in front of the starter, a specialized 5-pin module HEI distributor, and a small silver control module located behind the glove box. The knock sensor allows a high-performance engine with a 9.3:1 or higher compression ratio to safely burn 87 octane gasoline with no damage to the pistons when or if detonation and a pinging sound occurs.

How It Works: The knock sensor backs off (retards) ignition timing almost instantaneously - within milliseconds - the moment it detects the specific acoustic vibrations of detonation (pinging sound). It listens to engine vibrations to detect pre-ignition or spark knock. It sends a voltage signal to the engine control module so timing can be backed-off (retarded) to protect the engine from damage. On older popular Chevy small block V8 engines, this sensor is located on the lower passenger side of the engine block, in front of the starter motor. It threads into the coolant drain hole.

The rapid response operates in the following stages:

  1. Detection: The sensor (a piezoelectric crystal) detects the sudden shockwave of an uncontrolled explosion. It instantly converts these vibrations into an electrical voltage signal and sends it to the Engine Control Unit (ECU).
  2. Immediate Retardation: Once the voltage surpasses a pre-set threshold for knock, the ECU immediately retards the ignition timing to reduce cylinder pressure and stop the detonation. This usually happens in small steps (typically -2° to -3° per event) until the noise clears. If the knock is severe, it will pull more timing (up to -6° or more depending on the vehicle).
  3. Recovery / Re-learning: Once the knocking stops, the ECU holds the safe timing for a moment and then slowly begins advancing the timing back toward its optimal setting at a gradual rate (e.g., 1° per second).
  4. This continuous tug-of-war ensures the engine produces maximum power while keeping the engine safely out of a damaging knock zone. You can learn more about how this system balances power and safety on.
  5. You can detect the drop in engine power when a knock sensor detects pre-ignition (knock) and forces the Engine Control Unit (ECU) to retard the ignition timing.
  6. The signs range from subtle to severe depending on the severity of the knock and the specific vehicle.

Signs You Can Feel and Hear

Recovery Surge: Once the ECU determines the engine is no longer knocking, it will slowly advance the timing back toward its optimal mapping. This return to normal can feel like a sudden surge or pickup in power.

Continuous Power Loss: If you are running poor quality or low-octane fuel, the ECU might constantly stay in a "safe" (retarded) timing map. This results in an overall lack of pep and poor fuel economy across your entire drive.

Why This Happens (The Science)

How to Bench Test an HEI Distributor with the 5 Pin Ignition Control Module -

The knock sensor computer - officially known as the Electronic Spark Control (ESC) module - is protected by a fuse. If the vehicle loses power to this module, the engine will typically experience a "crank, but no start and no spark" condition. The fuse is located in the main fuse panel. It's part of the GAGE / IDLE fuse (typically a 20 amp fuse). If the dashboard fuel/battery gauges work when the key is turned to the "ON" position, this fuse is likely not burnt.

To test the Electronic Spark Control (ESC) module (the knock sensor "computer") with the engine not running, a key-on, engine-off (KOEO) voltage test must be performed using a Digital Multimeter (DMM).In 1985 GM systems, the ESC module sits between the knock sensor and the main Engine Control Module (ECM). When it detects a knock signal, it drops its output voltage to signal the ECM to retard timing.

1. Locate the ESC Module. The standalone ESC module is a small, flat plastic box usually mounted on a bracket near the firewall, passenger-side fender, right behind the fuel pump relay or on inside the firewall behind the glove compartment. It features a 5-pin inline Weatherpack connector.

2. Identify the Wire Pins. Look closely at the letter markings embossed on the distributor ESC plastic connector:

3. Step-by-Step Electrical Testing (KOEO)

  1. Turn the truck's ignition key to the RUN position (engine off) and set the multimeter to DC Volts. Ground the black meter probe to a clean spot on the engine block or battery negative terminal. Backprobe the connector pins while it is still plugged into the module:
  2. Test Power (Pin B): Touch the red probe to Pin B. You should see 12 volts (battery voltage). If you see 0 volts, check the fuses or the ignition switch circuit.
  3. Test ECM Reference Signal (Pin C): Touch the red probe to Pin C. With the engine off and no knock present, you should see roughly 8 to 10 Volts. This proves the ECM is providing a reference voltage signal down the line.
  4. Test the Knock Sensor Bias (Pin A): Touch the red probe to Pin A. You should read approximately 4 to 6 Volts DC passing through the module toward the knock sensor.

A simple way to test a knock sensor, is to start the engine, hold the idle at 1,500-2,000 RPM, shine a timing light on the harmonic balancer timing mark, and tap the engine block with a big wrench or small hammer. (This simulates detonation or pinging sound in the engine.) If the ESC module is working correctly, the timing mark will retard, then when the tapping stops, it will advance to its previous setting. Also, if the ESC module is working correctly, the engine RPM will audibly drop and stumble momentarily as the timing retards, then recover.

4. Simulating a Knock Signal (Engine Off)

  1. While keeping the multimeter backprobing Pin C (Signal to ECM):
  2. Watch the meter screen, which should currently be reading 8–10 Volts DC.
  3. Take a small metal wrench or hammer and firmly tap the engine block right next to where the knock sensor is threaded into the lower block drain plug.
  4. The Result: If the ESC computer and knock sensor are functioning correctly, the sudden acoustic vibration will trigger the module, causing the voltage reading on Pin C to instantly drop toward 0–2 Volts for a split second.
  5. If the voltage remains locked at 8–10 Volts during heavy tapping, either the knock sensor is bad or the ESC module is bad.

Diagnosing a Faulty ESC Module or Broken Wiring -

If you suspect the Electronic Spark Control module is faulty, diagnose it by temporarily performing a bypass. With the distributor installed in the vehicle, unplug the 4-pin weatherpack connector coming from the distributor and connect pins A and C together on the distributor end. If the engine starts and runs normally (albeit without electronic knock timing adjustment), this proves the ESC module or its wiring harness has failed.

How to Convert an Older Small Block Chevy (SBC) for Use With a Knock Sensor -.

To make this swap work, the transplant requires a three-part standalone system as a complete package: the 5-pin HEI distributor, the separate ESC control module box, and the matching knock sensor. Unlike modern vehicles, the early GM ESC setup (commonly found on carbureted vehicles from roughly 1980–1986) operates independently of a vehicle's main computer (ECM). The distributor still retains its traditional mechanical weights and vacuum advance canister to control the base timing curve. The ESC system is only there to dynamically retard timing if it detects engine pinging.

Be Aware of Mechanical Noise: High-performance aftermarket parts like loud, tapping solid lifters, noisy gear drives, or loose exhaust headers can trick the older knock sensor. This mechanical noise can cause the system to falsely retard the timing when no actual engine knock is occurring.

Required Components for the Swap. To successfully complete the installation, you must harvest the following matching parts from the donor vehicle:

Wiring Requirements. The system requires very simple wiring to run standalone on an older car or truck:

Carbureted GM vehicles equipped with the standalone Electronic Spark Control (ESC) knock sensor system were exclusive to specific 305 CID (5.0L) V8 engines (notably the high-output L69 and select LE9 variants), as GM did not use a standalone analog ESC knock sensor setup on carbureted 350 (5.7L) engines.

Carbureted GM Vehicles with 305 ESC Systems:

A GM squarebody truck with a Turbo 350 or similar setup often features two firewall-mounted vacuum-to-electrical switches because one controls the torque converter lock-up clutch and the other manages emissions or spark retard (Electronic Spark Control / EGR system).

The Two Switches and Their Jobs:

How to make the 1963-72 Chevy and GMC truck motor mounts super strong and easier to bolt back in when reinstalling the engine:

Drill a 7/16" hole through the rubber motor mounts, install a grade 8 bolt so the threads are exposed toward the lower part of the mount. And before installing the engine in the truck, drill the frame motor mount holes to 5/8". The exposed threads or "studs" on the motor mounts will allow for easy alignment to install. Then use wide flat washers, lock nuts and grade 8 nuts on the threads of each mount.

Adding an automatic headlight conversion to a squarebody involves installing a light sensor kit. Because the squarebody uses a highly-loaded, un-relayed factory switch, installing an inline headlight relay harness alongside the sensor kit is highly recommended to protect the factory dashboard switches and wiring.

Step 1: Gather the Tools and Parts:

Step 2: Install the Relay Harness:

  1. The C10 is notorious for running the full headlight electrical load through the firewall switch, causing dim lights and potential melting.
  2. Disconnect the negative battery terminal.
  3. Mount the relays on the inner fender or radiator support near the battery.
  4. Connect the heavy-gauge power wire of the relay kit directly to the battery's positive terminal (or the power junction block) and secure a solid ground to the chassis.
  5. Unplug the factory headlight connectors. Plug the relay harness's new, heavier plugs into the headlights.
  6. Route the trigger wires (usually Tan for low beam, Light Green for high beam) back to the factory wiring and connect them.

Step 3: Wire the Automatic Headlight Module:

  1. Mount the Control Module: Find a dry, secure space under the dashboard (e.g., behind the glovebox).
  2. Mount the Sensor: Place the photocell sensor on the driver's side of the dashboard base (against the windshield) where it gets maximum sunlight. Route its wire under the dash and plug it into the control module.
  3. Connect to Power and Ground: Run the module's ground to a bare metal spot under the dash. Connect the red power wire to a 12 volt constant or ignition-switched source (depending on the specific kit's instructions).
  4. Connect to Light Switch: The automatic module needs to "intercept" the headlight switch. Usually, you will connect the module's trigger wire (often green) to the power-in wire going to the pull switch. Refer to a trusted AutoZone GM Full-Size Trucks 1980-1987 Repair Guide to pinpoint the correct factory wire colors for the cabin's headlight pull switch.

Step 4: Test and Secure:

  1. Reconnect the negative battery terminal.
  2. Turn the factory headlight switch to the "Auto" or "On" position (depending on how the kit wires in).
  3. Test the sensor by covering it with your hand. The headlights should automatically turn on after a brief delay. Remove your hand, and the lights should shut off.
  4. Tidy and route all loose wires cleanly away from moving engine components, and secure them with zip ties.

How an Electric Choke is Connected on an Engine That Didn't Originally Come With One:

When retrofitting an electric choke onto an older engine that originally came with a manual choke cable or a hot-air/exhaust "choke stove," the electrical and mechanical setup typically involved the following methods:

1. Electrical Power Sources -

2. Grounding -

3. How the Electric Choke Functions Day-to-Day -

How to Connect an Automotive Electric Choke -

On a standard 12 volt electric choke cap, there is no positive or negative distinction between the inner/center and outer blade terminals because the internal heating element is a simple resistor. Electric chokes function using a bimetal spring wrapped around a ceramic ceramic heating element. Because it is a resistive load, current can flow through it in either direction to generate heat. However, how you wire them depends entirely on the style of the choke cap you have:

1. If the choke cap has two external terminals (one near the center, one near the outer edge):

2. If the choke cap has only one terminal:

An electric choke typically takes 3 to 5 minutes to fully open once the ignition key is turned on and +12 volts power is supplied to the bimetallic heating coil. And it typically draws between 1 to 3.5 amps of continuous current during normal operation, though it can experience a brief initial spike of 6 to 7 amps the moment power is applied to a cold coil.

Using a 2 Terminal Oil Pressure Switch to Activate the Electric Choke -

Operating an old-school electric choke from a three-terminal oil pressure sending unit/switch is better because it serves as a safety mechanism to prevent the choke from opening before the engine actually starts. While the alternator (specifically the stator or "S" terminal) was a common factory wiring choice for many vintage vehicles, upgrading to or utilizing an oil pressure switch provides distinct technical advantages.

The GM two-terminal oil pressure switch is used for both the dash light and electric choke, serving a dual purpose in many classic GM vehicles (such as older Chevy/GMC trucks and cars). The 2 terminal (or normally open) oil pressure switch acts as a switch for an electric choke, ensuring the choke's coil only heats up and opens the choke plate when the engine is running and producing oil pressure. General Motors introduced the 2 terminal oil pressure/choke switch configuration on small block Chevrolet (SBC) and related carbureted passenger car and truck engines around 1978–1979 as factory electric chokes and emissions requirements became widespread.

How the Two Functions Work Together:

Key Details of the Switch and System:

How the Wiring Works:

Operational State

With a 2 terminal oil pressure switch used for an electric choke (common in older GM and classic vehicles), the dual-function switch and dashboard warning light operate through a shared-power or ground-return logic depending on the factory wiring design.

How the Dash Light Works

Why the Oil Pressure Sending Unit is Better:

Feature Oil Pressure Sending Unit / Switch Alternator (Stator/S-Terminal)

The 2-terminal oil pressure switch (or sender) is not a single universal part; instead, it is a broad design category used across thousands of different vehicle makes, models, and engine sizes—ranging from classic American V8s and Jeeps to modern imports—depending on whether the vehicle uses an oil pressure warning light, an electric dash gauge, or a variable valve timing (VVT) system. Because exact fitment depends heavily on the specific part number (such as Standard PS-144, PS-284, PS-310, or ACDelco E1805A), applications vary widely by manufacturer:

Using an "Old School" 3 Terminal Oil Pressure Switch to Activate the Electric Choke -

How the "Old School" 3-Terminal System Works:

The classic GM style 3-terminal unit pulls double-duty:

  1. Terminal 1: Sends the variable resistance signal to the dashboard oil pressure gauge or warning light.
  2. Terminal 2: Accepts a fused 12 volt ignition power source.
  3. Terminal 3: Routes that 12 volt power out to the electric choke cap.

The connection between Terminal 2 and 3 is a physical switch that stays open until the engine fires up and creates roughly 2 to 5 PSI of oil pressure. Once pressure is detected, the switch snaps shut, sending a clean, steady stream of 12 volt power directly to the choke to let it warm up normally.

To safely and effectively wire an electric choke using an oil pressure switch, the goal is to supply 12 volts power to the choke only when the engine is actively running and building oil pressure. This prevents the choke from heating up and opening prematurely if the ignition key is left in the "RUN" position while the engine is off.

Step-by-Step Installation Procedure

  1. Mount the Switch: Install the 3-terminal oil pressure switch into an engine oil gallery port (commonly near the distributor or oil filter housing). If the vehicle already have an oil pressure gauge, install a metal T-fitting to run both the gauge sender and this choke switch from the same port.
  2. Wire the Power Input: Locate a 12 volt source that is hot only when the key is turned to "RUN" (do not use the accessory circuit or the "Batt" terminal directly without a keyed source). Run a wire through a 20-amp inline fuse to one of the outside terminals on the pressure switch.
  3. Wire the Choke Output: Connect a wire from the remaining outside terminal of the switch straight to the positive (+) terminal terminal on the electric choke cap.
  4. Ground the Choke Coil: Ensure the carburetor has a solid ground connection. If the choke cap has a dedicated ground spade, run a clean wire from it to a nearby bolt on the intake manifold.

The 3-terminal oil pressure switch (or sender) is not a single universal part; instead, a 3-pin or 3-terminal design fits a wide range of GM (Chevrolet, GMC, Buick, Cadillac, Pontiac) and other manufacturer applications spanning different eras—most commonly from the mid-1970s through the late 1990s and 2000s, depending on the specific engine and part number:

Using the Alternator to Activate an Electric Choke -

Using a GM Delco-Remy Alternator with an External Voltage Regulator to Power an Electric Choke-

To power an electric choke using a standard 4-pin or 5-pin automotive relay triggered by a GM alternator with an external voltage regulator (such as a classic 10DN setup), you can use the alternator's generator light (idiot light) wire or field/stator circuit to switch the relay on only when the engine is actively running.

Why Use a Relay?

An electric choke is essentially a small heating element. Powering it directly through a key-on ignition switch or tapping a resistor wire can draw too much current and burn out old switches or drop voltage. A relay lets you feed a clean, full 12-volt current directly from a heavy-duty power source without overloading the harness.

Standard Relay Wiring Method (Engine-Running Trigger)

Using a standard 30-amp/40-amp automotive relay, wire the terminals as follows (referencing standard relay pin numbers):

How it works: When you turn the key, the relay stays off. Once the engine starts and the GM alternator begins charging, the trigger signal on Pin 86 energizes the coil inside the relay, closing the internal switch between Pin 30 and Pin 87. This sends full 12V power to the electric choke only while the engine is running—preventing the choke from heating up if you leave the key in the "ON" position with the engine off.

Using the Electric Choke with an Alternator with a Built-In Voltage Regulator -

On a GM Delco-Remy 10SI alternator, Terminal 1 (the brown wire/exciter/stator/indicator light side) was used by GM and Ford to trigger a relay that powers the electric choke. However, connecting Terminal 1 directly to an electric choke without a relay is generally discouraged because the choke coil draws more current than the indicator/exciter circuit in the alternator is designed to handle, which can damage the alternator or cause the choke to cool down and close if the alternator quits working or if the fan belt breaks. Instead, it's recommended to use a dedicated relay as mentioned below or an oil pressure switch as mentioned above.

Even a standard 12 volt automotive electric choke relay (such as Standard Motor Products RY-144 or RY-28) that's triggered by the ignition, doesn't work as well as the oil pressure switches mentioned above because the relay sends power to an electric choke coil full time only when the ignition is on or when the engine is running. The relay system works fine when the key isn't left on for a long time or when the engine starts quickly.

Understanding Terminals 1 and 2:

The term "idiot light" (or dummy light) came about in the mid-20th century as a sarcastic nickname for simple on/off dashboard warning lights that automakers began using to replace traditional mechanical gauges.

How and Why It Started:

How to Use a Relay to Protect from Damaging a GM Delco-Remy Alternator -

A horn relay, blower motor relay or any standard 12-volt automotive relay can technically be used to power an electric choke when it is connected to a GM alternator, provided it is wired correctly.

How It Works:

Best Practices

Any standard SPDT 12 volt, 30-to-40-amp automotive 5-pin or 4-pin relay (such as a horn or blower motor relay) can be used to power an electric carburetor choke.

Types of Relays Used

The alternator-controlled electric choke circuit, commonly used on older vehicles (like vintage Fords or GMs) to ensure the choke only receives power when the engine is actually running. In this setup, the relay is triggered by the alternator's stator or field circuit, which then closes the contact to send 12 volts directly to the electric choke coil. If you are using a standard 12-volt electric choke and want to avoid overloading the alternator stator, a 30-amp, 4- or 5-pin standard automotive relay is the best approach.

How a Relay Setup Works:

When an electric choke relay goes bad, it disrupts the power supply to the carburetor's electric choke coil (or the choke warning light circuit), causing the choke to either stay closed or fail to heat up properly.

Common Symptoms of a Bad Electric Choke Relay

How Many Amps Does a Relay Draw Compared to an Electric Choke?

A standard 12 volt automotive relay coil (the control side) draws about 0.035 to 0.2 amps (35 to 200 mA), whereas a typical electric choke draws about 1 to 7 amps (starting around 5–7 amps cold and dropping to roughly 1–2 amps as it warms up).

Current Draw Comparison:

Key Electrical Details

In most cases, a weakened pressure relief spring in the oil pump causes low oil pressure. Therefore, I stretch the relief spring about 3/4" out past the housing in all of the stock oil pumps in my small block Chevy engines, and they produce around 40 - 55 PSI at idle when warmed up, and 80-100 PSI at highway speeds when warmed up. I'm not worried about the spring breaking because these are made of extremely tough material. Anyway, the increased pressure slings more oil from the rods onto the cam, lifters and cylinder walls. It also fills the hydraulic lifters more for quieter valves. I also drilled a 1/16" hole through one of the lifter oil galley plugs so oil can squirt/spray on the timing chain/sprockets, allowing these parts to last longer. Also, high oil pressure with stock/baffled valve covers may also cause the engine to burn oil through the PCV valve. A restrictor with a .3/32" hole placed in the PCV hose will prevent this. And most standard passenger car oil filters are designed to withstand minimum burst pressures of 200 PSI, which is roughly double the normal maximum operating pressure of most engines. Anyway, of all the 10+ engines that I've built since 1979, they're still going strong at 350,000 - 400,000+ miles with regular maintenance and oil changes, and no oil burning or weird sounds. This works better, and it works great. No joke.

In most cases, rather if it's a gas or diesel engine with solid lifters, insufficient valve clearances will prevent an engine from starting or it'll make it hard to start. Therefore, each valve will need to have the clearance reset to factory specs. And with the proper clearances the engine should start faster, idle smoothly, rev up quicker and produce full power.

New flat tappet lifters are ground to be slightly convex with a .001" dome, and the lobes on flat tappet cams are ground to have a .001" slope. This allows the lifters to grip and rotate on the lobes when at full lift each time the valves are opened to prevent wearing of both the lobes and lifters. The base of used lifters that's in good condition can be dressed with 400 grit sandpaper to give them a slightly convex with a .001" dome and rough surface to grip the cam lobes and create a new wear pattern.

Copper coat spray works great on head gaskets. I use it sometimes. But aluminum or silver paint also works great. Aluminum or silver paint melts when the engine heats up, creating a perfect sealing surface.

I never use gaskets for my exhaust manifolds and headers. Instead, I apply clear RTV silicone sealant and torque the bolts to specs. The reason being are: 1. silicone will not burn due to exhaust heat; 2. it fills in any imperfections between the two metals to prevent leaks; 3. the manifolds or headers will not warp between the bolts when the bolts are torqued: which is where the gaskets usually burn out, and 4. it provides a perfect flat sealing surface against the cylinder heads. And when silicone is used with headers, which provides a more or less metal to metal contact, the bolts will not loosen.

A true "cold air intake" is when the engine's intake air filtration system draws cool air from outside the engine compartment, preferably through the grille. This allows the engine to produce more power and better fuel economy. If it draws air within the engine compartment and from behind the radiator, it's considered a "hot air intake." And this causes the engine to make less power with poor fuel economy.

I'm an old-school hot rodder. One day, I met a nice lady named Holly. I said to her, "Hi Holly. I like your name. It reminds me of a 4 barrel carburetor." Then I found she has a sister named Dana. When I saw her, I thought to myself, "Dang, she has a nice rear end!"

Ford oil pump driveshafts are categorized primarily by hex size (1/4-inch or 5/16-inch) and block/deck height. The 1/4-inch hex driveshaft is most famously shared across the classic Ford Windsor small-block V8 family (such as the 221, 260, 289, and 302 cubic-inch engines), as well as standard Ford FE big-block V8s like the 390.

Engines Using a 1/4-Inch Hex Driveshaft:

Engines Using a 5/16-Inch Hex Driveshaft (Not Interchangeable)

Which oil pump driveshaft material works better than the OEM one in a Ford engine?

Heat-treated chrome-moly steel (specifically 8740 chromoly or ARP2000 alloy steel) works much better than the stock OEM shaft. Popular upgrades like the ARP Oil Pump Driveshaft Kit or Ford Performance Heavy Duty Oil Pump Shaft feature a larger diameter and higher tensile strength to prevent catastrophic snaps under high RPM or heavy oil loads.

Why Chrome-Moly Outperforms OEM:

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To place an order, please send your item(s) for repairing, and/or for customer service assistance, and FREE honest and accurate technical support, contact: A-1 Miller's Performance Enterprises, 12091 N Route B, Hallsville, MO (Missouri) 65255-9604 USA. Please call in your order or send an email with a list parts you need and your contact information. Phone: 1-573-881-7229 (cell; call, text or leave voicemail). Please call Monday-Friday, 9am to 5pm, Central time zone, except holidays. If no answer, please try again later. Please be patient when speaking with me on the phone because I stutter. E-mail: pullingtractor@aol.com. A-1 Miller's shop is open to the public Monday-Friday, 9am to 5pm, Central time zone, with an appointment on weekends, except holidays. If you're the kind of person who don't trust delivery/shipping companies (mis)handling your high-dollar and fragile merchandise, you can make the long drive to A-1 Miller's new shop (click image to the right) to personally purchase parts, or drop off and/or pick up your carburetor, clutch assembly, and/or other parts for repairing and/or rebuilding. Or visit our new shop to drop off your parts. Please contact us before coming so we'll be at our shop waiting for your arrival. When you visit our shop, you will be dealing directly with the owner for the best customer service. "The road to a [trusted] friend's house (or shop) is never long." Don't sacrifice quality workmanship for distance. Payment Options below. Photos of our new building/shop are posted here! 12091 N Route B, Hallsville, MO - Google Maps. The reason I have never made any YouTube videos is because I stutter. I'm afraid the viewer's mockery and negative comments would take all the educational benefits and fun out of them.

Payment Options, and We Ship to Canada and Worldwide
Item(s) in a package or cushioned envelope weighing less than 1 lb. is sent by US Postal Service Airmail Letter Post for a 4-7 days delivery. Packaged item(s) weighing over 1 lb. and up to 66 lb. is sent by US Postal Service Airmail Parcel Post for a 4-10 days delivery. I cannot use the US Postal Services' Flat Rate Priority Mail envelopes and boxes to ship outside U.S. territories. Item(s) weighing over 67 lbs. or more is sent by FedEx Ground or equivalent services. We try to keep our shipping cost to customers within reason. Therefore, we don't ship our products in a fancy-looking package with our company name and/or logo on it because most customers will just toss it in the trash after they remove the contents. And being there is no USPS tracking number outside the US, all I can do is make sure I write your address correctly on the customs form and on your package.

My websites are not set up to process orders and accept payments. Therefore, I will need your name, complete and correct postal mailing address and phone number. And for payment options, I accept cash (in person), USPS Postal Money Orders, cashier's checks and business checks. I do not accept credit/debit cards. Or to make a payment to me through PayPal, please click this link: https://www.paypal.com (username: pullingtractor@aol.com). And please use PayPal's "Friends and Family" option to ensure that I receive the full amount or add 3% to the total amount to cover PayPal's processing surcharge. I also accept Venmo (username: Pullingtractor) and Cash App (username: pullingtractor) please add 2% for Cash App's surcharge as well). And be sure to mention a description of what the payment is for with your full name, postal address, phone number and email address. If sending a money order or cashier's check, please include a note in the envelope with your name, complete mailing address, phone number, email address and a description of what the payment is for. I'll make a note of your order when I have all your information, and I may have to order some of the parts on your list, which should take a few days to come in, but I will send everything to you as soon as the parts are in stock after I receive your payment.

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