Sorry if I'm posting in the wrong place, b ut this is a stroked motor and complete re-build.

I know this is a third gerneration Camaro, but the way the engine has been modified it's like a first or 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

 

Dave,

I had a similar issue (not as severe) and found a few things to tune.

Read the thread, "Increasing Vacuum at Idle & Canister Operation" within
this forum.

I'm sure the points within that discussion will lead you to the root cause.

 

More thoughts:

Common areas I've seen are incorrect valve adjustments (pre-load).
Don't use the manual. You must set each valve independently for best
results. Turning the crank twice and setting a set of valves all at once
certainly doesn't yield the best performance.

Also be aware of how much pre-load is set after the zero lash point.
You don't want to be turning the adjustment nut more than 1/2" turn
past zero lash. For peformance apps., the lifters seem to like modest
amounts of pre-load (0.005-0.010") which equates to about an 1/8th
turn.

Vacuum leaks are also a huge issue. Buy a vacuum gauge and check the
idle vacuum. Intake gasket leaks, carb base gaskets, any hoses plugs connected
to the carb ports are suspect areas as well.

You may also use the vacuum gauge to set the idle mix and determine whether
the power valve is the correct value.

The power valve in the primary side of the carb should be at least 2 points
LOWER than the reading on the vacuum gauge to avoid opening and dumping
excess fuel at idle.

 

If you can't get it figured out.... go to FLP in Naperville. 630-820-9294. Dan at FLP will be able to get your car running right.

 

So in manual first gear the car goes just fine? But in OD (normal drive position) it bogs like crazy and stalls out? Sounds to me like you got something screwy with the Lockup clutch because it wont come on in manual first gear. May be a shot in the dark, but pull the 4 prong plug off the tranny and then try it.

 

I don't think it's transmission related because the engine wont idle properly.

My car would still light up the tires in first, but would have trouble idling until
I messed with the timing and carb adjustments.

 

What are the cam specs
I just built a wild 327 for my 2nd gen
now it was a three speed but same problem
from the sound of it the lockup is on
but if the stall is too small it will have trouble ideling
in gear find out what the cam is and the specs and it will be easyer
to troubleshoot

 

i'd like to see what the engine pulls for vac, and know what the timing is at idle with the vac advance disconnected. if you list the things the other guys have already asked it should be fairly obvious if its an engine related thing. also whats the exhaust fumes like, any smoke or raw fuel (burning eyes) etc etc?

 

10-4 GUYS I knew this was the place to post! Based on all your responses I have alot of work and answers to do and gather over the weekend. I will post up as much as I can determine for a better diag. I did have my son put the vacume guage on it and it's 3! I'll have the cam specs when I get home Monday.
Thanks
Dave

 

3 ?!

There's the answer...now what combination of items are causing this?

Be certain you check the power valve, it's probably a 6.5...you'll need something
in the order of a 2.5 (and hope to steal at least another 2 points of vacuum
with any luck in your troubleshooting)

 

you made sure he put it on the manifold vacuum right? as in the port bellow the throttle blades. 3" of vac... gees thats pathetic its got to be severly out of tune or have a massive leak somewhere.