Camaro Won't Idle in Drive

I know this is a third gerneration Camaro, but the way the engine has been modified it's like a second. I am a former 1st gen owner. I am hoping someone might be able to point us in the right direction or help us find a performance shop in ChicagoLand that could help.

This is all about my 17 year old son’s high school senior auto project from last June when he graduated. He has dreamed of owning a Camaro sinse he was a little kid.

In October of last year he bought a 91 RS with a 305 with a stock 700R4 Trans. The car was all stock with 90k miles on it. He pulled the engine and replaced it with a 350 (from a Chevy 2500 passenger van)that he re-built and he had it punched and stroked to a 383, 9.7:1 pistons a fairly hot cam (I don’t know the exact specs), an Edlebrock dual plane manifold and a Holly 750 and headers. He is using the stock 700R4 trans with a 2500 stall converter. He changed the rear end out to a posi and disc brakes. The timing seems to be set correctly. The fuel pump is a Holley electric. It shows 7psi at the carb. That seems low to me, but I’ve been out of the game for so long now.

Here’s the problem. The engine starts and runs and revs good, but won’t idle below 1000rpm. If he adjusts the idle over 1000rpm to keep it running and drops it into drive it dies. It just won’t idle in drive. The carb seems to be adjusted according to the manual. He can drive it, but he has to ride the gas and brake and we all know that’s bad. The car has no guts in drive, but in 1st it hauls butt.

I don’t know where to go from here. My Camaro was a 67 302 in 1975 and it’s been so long I don’t have the skill or knowledge to help him. He is out of school now and his shop teacher kinda pushed him out the door last June so he’s no help.

This kid has so much time, effort, sweat and money in a car that just won’t run for him. He starts Triton University in the advanced auto program in a few weeks and he is interning at our local Chevy dealer. Even the mechanics there are at a loss. He is starting to get discouraged and he is a really decent kid. I gotta find a way to help him figure this car out.

Any guidance would be greatly appreciated.

Dave

After the ECM takes control of the timeing and adjustments when the car has been runiing for a few minutes does the timing stay on the correct marks? If you arent sure just start the car let it idle for like 3 or 4 minutes. You should hear a change in the idle when the ECM kicks in. Check the timing. If the timing seems to be off after that, you may want to look into bad sensors or prolems regarding the ECM or corresponding parts.

I say that because I have an 87 camero, we rebuilt the engin and we couldnt get it to run correctly. The ECM was advancing the timing way to far and so I had bad preformace if my RPMs were low. If I hit the gas really hard and made the RPMs jump it ran ok because I think when its working right the EMC advances the timing when you jump on the gas, anyway, I found that my MAF (mass air flow sensor) was bad and so giving the ECM bad data.

OK, since you said he put in a carbed engine we can assume that he no longer has the ECM doing anything. Was the distributor changed to a vacuum advance version? The stock distributor won't work without the ECM because the computer did all of the functions that the vacuum advance did in the "old days"
Also, you said he kept the 700R4 transmission, the 700R4 has a lock up torque converter that is controlled by the ECM (computer). If the converter is locked up at idle it probably will kill the engine when put in gear.