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Freshen and Upgrade Your Corvette's Ignition

Put the spark back in your relationship with your Corvette


Stock GM Ignition System

The stock GM ignition system works well, but you can upgrade it and get a better spark and snazzy red components for not much more money than stock replacement parts.

Photo by Jeff Zurschmeide

One of the wonderful things about Corvettes is that from 1955 to 1991, most of them were delivered with GM's venerable small block or big block V8 engines. Yes, there were some '55s with the Blue Flame 6, but just a few.

This is good news for an article about refreshing the ignition on your Corvette, because the standard Chevy V8 ignition distributor is the same for both small and big-block V8 engines used in Corvettes. In 1992 when Chevy put the LT1 engine in the Corvette, they used a new and different distributor, so owners of late C4s and all C5 and C6 models will have to wait until I can photograph an ignition tune-up on an LT or LS engine for their cars.

But there are about a million Corvettes out there that use the basic GM V8 distributor, whether with points or the HEI electronic ignition, so this procedure should cover most Corvettes on the road today.

Restoration or Upgrade?

One of the key questions facing a Corvette owner who needs to freshen up the ignition is whether to restore the Corvette's stock ignition components or upgrade to newer and better parts. Particularly, if your Corvette was made before 1975, the stock ignition system uses contact breaker points, a condensor (capacitor), and an oil-filled high-tension coil to generate the spark. Corvettes from 1975 and onwards use a solid state electronic ignition module and a coil that is integrated into the distributor cap.

If you wish to restore your Corvette to factory-original standards, you must use the correct original parts, right down to the spark plugs. This also includes the points (or HEI module), the distributor rotor, distributor cap, coil, and plug wires. There's nothing wrong with these parts, and your Corvette will run just fine with them, as long as you keep them fresh, adjusted, and properly maintained.

However, you will find that the HEI system is a big improvement over points and a separate coil, if only because it does not require adjustment apart from overall spark timing, which you set by turning the distributor body. You can also purchase higher-performance parts for HEI distributors on the aftermarket, and thereby get a hotter spark than the stock parts will deliver. If you do decide to go from points to HEI, you must replace the entire distributor.

The choice is up to you. If I had an NCRS Top Flight 1962 Fuel-Injected Coupe, I'd use stock parts from bumper to bumper. That's the right thing to do. However, I have the About.com Project Corvette, and as a 1977 model it already has HEI, so I decided to go for the full suite of upgrade parts from MSD.

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