Thread: New member needs help with sbc350!

Tweet

Ok here are the specs.....

2bolt 1995 casting GM350 with the 87-95 cast iron centerbolt heads (non vortec)
9.0:1 compression
Cam Specs 232/232 @.050 .466"/.466"
Intake is a Professional-Products Typhoon dual plane 180deg square bore #52020
Carb is a Barry Grant Road Demon 625 with vacuum secondarys and electric choke.
Mallory HEI 8548201C
Carter electric 6psi 90gph fuel pump


Ok here's the problem. The engine starts up fine but idles at 1200-1400rpm at it's lowest. Anything less and it stalls out and blows fuel/smoke (something) up through the carb. When at 2400rpm it sounds like it's straining to run. This is my first carbed engine and I'm not sure if it's a timing issue or some type of vacuum leak.

What do yall think?

I'd be thinkin' vacuum leak. Even if you can't find one on the outside, it could be suckin' into the intake ports from inside the motor. Read this.
http://streetmachinesoftablerock.com...opic.php?t=350

Hmmm interesting.

I just bought a timing light last week and have not had time to check where exactly it is...... Once I do this I'll be doing the external vacuum leak checks.

It was started a couple weeks ago and could not be tuned at all.... it was non-responsive to anything.

Can there be a problem with the carb..... such as a fuel bowl problem. I ask this because the first pump that was installed was unknown and when the key was turned, it pegged the fuel guage to well over 14psi. It was later found that it was an 18psi pump at 130gph. It has since been replaced with a 6psi pump.


Another question I have is regarding the fuel system. I'm running a circle track style red/steel fuel cell in the bed. There is no return line on the system, only a feed and vent. The vent scares me- it's got a constant vapor leak on it. Is there some type of check valve or ball valve I can install on this thing to keep the vent from venting out all the time? I thought it was a vent that let air in as the fuel was used and figured it had a check valve in it already- I guess not.

Either plug the vent and use a vented cap or use a closed cap and use the vent. Your choice. The guys at the drag strip use rollover valves and run a piece of hose to the outside of the car if the cell is enclosed in the car. If you don't want to run a check/rollover valve, just run some hose to the underneath of the truck and attach a small air filter element to it to prevent dirt from entering the cell, but still allowing the cell to breathe.
http://www.atlltd.com/technical.htm
Click vent valves.