Hey everyone, first off I'm a new owner of an 81 Vette I'm working on fixing. First off I have a question about timing, I set it at 8 deg BTDC yesterday at about 800-850 rpm is that correct? My label on the hood is missing and the manual says to check there.

The choke wire needs to be connected to a 12 volt source that energizes when the key is turned on.  If you can get a wire back to the fuse block there should be a accessory terminal that is energized when the key is turned on.   If you decide to splice into a wire in the engine compartment use a multi-meter to be sure it is only energized when the key is in the on position.  If it is continuously providing 12 volts to the choke it will drain your battery.

Is it possible that your harmonic balancer has spun and is not lining up correctly?  I went thru 3 of them before I was able to get it to work.

The bad news is I don't know of a way to check them without replacing them.  Go with an AC/Delco part, not an AutoZone or other aftermarket part for this or you may be chasing this for a while if it is the issue.

First off, thanks for the responces. Alright choke seems pretty easy then, I wasn't sure if it was adjustable and had a voltage range that gradually closed/opened it.

Could be a holley shut down solenoid, I have one on my Holley 750 double pumper. Its on the driver side and when the ignition is turned off the fuel is shut down, mine would run after shut down, Holley sent me this to stop it and it worked. If your choke is electric and not hooked up that could be most of your problems, I would work on that first..

Dieseling after shutting off is caused by:
Vacuum leaks below the throttle plates
Idle too high
Fuel mixture too lean
Timing too advanced

800/850rpm idle sounds a little high to me for a standard trans car. Try setting it down to around 600/650rpm.

The solenoids used on the later cars are to solve this very problem. Unlike the early cars, that used to solenoid to raise the rpms when the A/C was on, later cars used it to raise the rpms for idling purposes. With the key on, the solenoid would extend, and keep the throttle at idle speed. When the key was turned off, the solenoid will retract, closing the throttle completely, eliminating the run-on/dieseling.

If the carb has been replaced, I assume the computer is not used anymore.

Hey guys, thanks again for the tips. I just went outside and checked all the vacuum lines and sprayed carb cleaner on the gaskets to check for a vacuum leak or improper seal.

Dieseling can be caused from a too lean mixture, due to the cylinder temps being high from a lean condition. If the tops of the pistons, or even the spark pugs themselves are super hot, the engine will want to continue running.

Now...about this "fuel pressure" adjustment from the side screws on your Holley. The only screws on the side of a Holley that I'm aware of are the idle mixture screws, and the float level "windows", that allow you to see/adjust the float level.(The actual adjustment for the float level is on the tops of the fuel bowls.)
If you screw the two idle adjustment screws all the way in, it may very well keep the car from running after starting it, since there wouldn't be enough air entering the idle circuits.

The specs for the timing is 8deg for the manual trans, 6deg for the auto. I forgot to look to see what the idle speed was...I'll pull it up again in the morn.

Oh, ok well that explains a lot I wasn't really sure I just assumed they adjusted the fuel pressure, excuse me I'm still in import mode .  I did get the choke fixed and I believe it's working properly.

I did suspect overheated carbon deposits as a possible cause, but even if I turn the engine on for like 5 seconds then turn it off it still diesels. Would the carbon be hot enough to ignite fuel in that short of time? I don't have any way to measure my A/F ratio.