C3 Tech/Performance V8 Technical Info, Internal Engine, External Engine, Basic Tech and Maintenance for the C3 Corvette
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Old May 15, 2025 | 01:19 PM
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Default Hei tuneup

Thinking it might be time to give my 1978 L82 a tuneup. Have no idea how old the cap, rotor, plug wire, coil etc are. I've owned it 15 years, 30k miles.Please comment on my plan:
New air filter (I have changed that before)
New distributor cap
New rotor
New coil,
New 4 prong ignition module
As I understand it, changing the pick up coil assembly require disassembling the distributor. Not going to happen by me! Is there a way to test the pickup module?
. Next thought - Jets and Summit have complete new distributors for less the the cost of the above parts. Sounds to good ? Are they good and reliable or
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Old May 15, 2025 | 01:49 PM
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Originally Posted by biackbenz
Thinking it might be time to give my 1978 L82 a tuneup. Have no idea how old the cap, rotor, plug wire, coil etc are. I've owned it 15 years, 30k miles.Please comment on my plan:
New air filter (I have changed that before)
New distributor cap
New rotor
New coil,
New 4 prong ignition module
As I understand it, changing the pick up coil assembly require disassembling the distributor. Not going to happen by me! Is there a way to test the pickup module?
. Next thought - Jets and Summit have complete new distributors for less the the cost of the above parts. Sounds to good ? Are they good and reliable or
Definitely do not change the 4 prong module. The ones they sell today are not very reliable. If it aint broke, why fix it until it is?

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Old May 15, 2025 | 01:58 PM
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For me, if the plug wires are 15 years old I'd be replacing them also.
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Old May 15, 2025 | 06:08 PM
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A few things to consider. Cap, rotor and wires. YES.
Now, replacing a good coil with a aftermarket coil could really bite you in the butt. Also, replacing a perfectly good module with a aftermarket module, not really a great idea. Maybe purchase one and keep it for a spare just in case.
check those little nylon bushings on the fly weights while your in there. These wear out.
As per one of those cheap HEI's available just about everywhere. There's a reason they are cheap. It's not likely to have the same or even similar timing curve. It's not likely to have a vacuum advance can that will even be close for your engine. I personally would advise against it.
A quality custom built HEI from DUI is a excellent replacement, however certainly not cheap.
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Old May 15, 2025 | 07:51 PM
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What timing spec are you aiming for?

Even if you change zero parts, getting your timing just right could transform your car for the better.

At that point, the DUI distributor becomes appealing.
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Old May 15, 2025 | 09:23 PM
  #6  
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Agree on not replacing coil or modules..
my advice is these are a bargain plug wires genuine GM OE part.
https://www.corvetteforum.com/forums...-question.html

plugs i would for sure go NGK. Ac delco chinesium and too long compared to original.

cap rotor? Napa or try NGK or ac delco oe if you can find it. Running wires is tedious.
also agree on timing engine for performance.
good luck

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Old May 16, 2025 | 08:31 AM
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Biackbenz,

Usually, you can get a little price break if you purchase Cap & Rotor as a set. Shy away from cheap material and spend a little extra on heavy duty caps.
Those better, thicker, heavier caps also have the quality brass terminals.
Check out Summit for those sets and you may find colored caps to match your engine bay.

Most of the caps come with a high resistance Spring Bushing under the coil. You may want to opt for a low resistance Bushing ($20) as those will not overheat.
MSD makes all of the above parts.
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Old May 17, 2025 | 11:01 AM
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Originally Posted by Bikespace
What timing spec are you aiming for?

Even if you change zero parts, getting your timing just right could transform your car for the better.

At that point, the DUI distributor becomes appealing.
Exactly! Davis will put a curve in the distributor tailored for your car. No fuss no muss.
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