I bought a 1981 Corvette that is not running.

The original Rochester Quadrajet carburetor has been replaced with a Edelbrock carburetor.

I think the original distributor has been replaced with the "coil in the cap" GM HEI style distributor because there is an old carb and distributor in a box that looks like it has been stored out in the weather for the same number of years.

I have a feeling that the original Computer Command Control system has been bypassed since the carburetor and distributor have been replaced?

i.e. the carb replacement probably forced the distributor replacement since the original distributor did not have the vacuum advance?

The car is not running. No ignition. Last inspection sticker was 3 years ago. I was told that the car did run for several years with the Edelbrock carb and replacement distributor before a brake issue parked the car.

Plan A would be to rebuild and re-install the Rochester Quadrajet carburetor with the CCC controlled mixture and re-install the distributor with the CCC controlled spark advance. This sounds like a safe decision.

Plan B would be to scrap CCC and make this an old fashioned car with an old fashioned Edelbrock carburetor and old fashioned vacuum advanced timing on the distributor. Something about scraping the CCC worries me. I read that the CCC is also involved with the transmission to lockup the torque converter clutch in second and third gears when traveling at a steady rate of speed? But apparently this car was operating with the replacement old fashioned carb and distributor... maybe with a glowing "check engine light" on the instrument panel? Maybe other issues?

This car still has the belt driven air pump or "smog pump" on the engine that pumps air into the exhaust to improve emissions.

This car still has the catalytic converter with o2 sensor installed.

I like the idea of an old fashioned simple carb and distributor, so maybe I should not have purchased a 1981 with CCC. But this what I found and purchased.

Any advice?

Are most 1981 corvettes running around out there still using the CCC ignition and emissions controls? Is that the only way to go?

Is there better performance if you do not use the CCC? What issues will you encounter?

I can imagine if you replaced the intake manifold, you would buy an Edelbrock Performer that would not have the EGR and would dictate bypassing the CCC also?

Is this car too new to turn into a hot rod?

Thanks for any advice from anyone knowledgeable about 1981 Corvettes.

 

i have had my 81 for one year. i have removed the air pump and put in true dual exhaust 2.5 " ss with magnaflows.i took put the stock headers and removed the air injector tubes and welded up the holes and put them back in the car. it still has the CCC and the original q-jet carb. No issues with the check engine light. and it runs great. If i were you i would keep the stock intake which is an aluminum edelbrock 2101. try to get an original q-jet they are a 750cfm. good luck and enjoy your toy

 

First of all, it should be very easy to tell if the distributor has been changed. The CCC distributor from a stock 81 has a long plug (six connections I think). If your distributor has this additional plug, it is stock. If the only connection to the distributor is a single, pink wire, it is an aftermarket one, which is fine. Check the pink wire for power with the ignition in the "run" position. If you have power, you're good to go. If not, that is your ignition problem.

You will also need a vacuum advance if your six connection plug is gone.

Since your computer controlled carb is gone, you no longer get any benefit from the CCC system. Essentially, the purpose of the CCC is to vary the amount of fuel from the adjustible mixture screw. With the carb gone, the only possible function from the CCC left is to lock up the torque converter at highway speeds. Since the distributor and carb are probably gone, I doubt this will work anyways. No worries though, this is easy to fix once you get that far.

Last, though your air diverter valve probably won't work without the other components, it will still pump air into the exhaust. I won't be as efficient as a properly working system, but it won't do any harm. Same with the cat. It'll produce a lot of backpressure, but otherwise will work fine without the CCC.

As for performance, the real bottlenecks in power in the 81 are the exhaust and the heads. The CCC system, when working, works fine.

 

If you have the original carb and distributor I would rebuild them and put them in and see where you get with it. If you don't have to deal with smog inspection, ****** off the air pump system to clean up the engine bay a bit. Fix the brakes and see what ya have at that point. Then start the mods: exhaust to start, cam and lifters, fancy floor mats and so on

 

First, get it running, then decide about ccc. In general some do mild setups w/ the ccc.
No Ig. is probably Ig. module or pick up coil.
No, not too new for a hot rod. I much prefer -80.

 

PS
It did not come w/ an aftermarket Edelbrock 2101 from the factory. The Q-J basically sizes itself to the engine so the 750 rating is not relevant as all the capability is not used on a stock, mild 350.

 

My 81 runs very good with the computer set-up. I believe the only devices that can cause the check engine light to light are the carb, dist, oxygen sensors, and the vss speed sensor on the back of the speedometer. I recently removed the smog pump from my car with no problems at all. SixFooter is correct, the engine bay looks much better.
Hopes this helps....Tim

 

The original CCC set up has no performance limitations. The original carb will out perform any Edelbrock carb. You can buy a new CCC distributor at NAPA for just over $100 and it comes with the new ignition module (I actually have an extra sitting around if you are interested). The original intake is fine.

The TCC on the tranny can be set up easily to work without the computer, so that should not be your deciding factor.

Yes, dump the smog pump if you can and get a freer flowing exhaust system as your first step in making it a "hot rod".

Do you still have the computer (just ahead of the battery) and wiring harness in place? If so, I would go ahead and rebuild the original carb, get a new distributor and go ahead and do a basic tune up (plugs, wires, cap, rotor).

God bless, Sensei