Engine Racing at Cold Start

'79 Impala ... 350 V8 ... Roch quad carb ... electric choke ... no A/C ... auto trans ... no vac leaks ... no EGR ... no EFE ... Edelbrock intake.
How do I lower the cold start initial rpm? Is it simply the fast idle screw adjustment or is there more involved? Adjust with engine running or not? Adjust with engine cold or warm? Thanks!

I had a qjet on mine that i replaced a 1406 edel but from what I remember the fast it idle screw should be on the bottom front right side lookino with the header panel in of front of you.
Should be done cold since it'll be off the fast idle cam when it warm
Set ur fast idle the snap the throttle fast idle should disengage and idle lower

Thanks for your reply. I've gone the opposite way and ditched my Edel 1406 for a Roch quadrajet. The Edel leaked fuel and I didn't like that there was no possibility to vent vapors from the fuel bowl to the charc canister. I wish you better luck than I had.

Here are a couple of pics of the fast idle screw. It is tough to get at when the carb is on the car but it can be done. If you set the choke with the car cold (one pump of the gas pedal) you will see how much gap is between the base idle screw and the stop. If you turn the fast idle screw a little you will see the gap tighten on the base idle screw and it will give you an idea of how much you changed the fast idle.

The red circle is where the fast idle screw contacts the fast idle linkage and the blue circle is where the fast idle cam contacts that linkage. Make sure the fast idle cam moves freely.

Thank you for the pics. They help.

paulboncz wrote:Thanks for your reply. I've gone the opposite way and ditched my Edel 1406 for a Roch quadrajet. The Edel leaked fuel and I didn't like that there was no possibility to vent vapors from the fuel bowl to the charc canister. I wish you better luck than I had.

Funny u say that since in getting issues again with vacuum leaks at the throttle shaft
Wanted to tune and blades closed and idle screws shut it still idles fine so got some crab spray right at the primary shaft and almosted stalled
It seems its the linkage setup is what wears it out , in using those cheap $10 adjustable ones I don't know if that's my whole issue because I use a TV cable for the th200 metric so it pulls the lever from above (throttle cable) and below(trans cable) with the spring keeping tension/ waerung out the aluminium body . thinking of getting a q jet from natonional carbs since I still have the oe brackets
Never had a issue with it but let my buddy talk me into rebuilding it and never ran right ,flat past part throttle
Was thinking of the lvl 2 qjet since I have aftermarket intake , pertronix hei coil/module and a set of vortecs being prepared for the near future
Any thoughts?

I am the wrong person to offer you any technical advice. You and I are in a different category. First, I want nothing more than stock performance from my vehicle, whereas you are looking for enhanced performance. Second, you obviously work in the engine bay yourself - which is great - but I don’t. Third, I make too many bad decisions, for example my ’79 Impala. I swapped out the stock 305, distributor, intake and dualjet for a package from jegs.com. The package included a 350 crate, HEI distributor, Edel intake and carb. This was dumb for someone who is happy driving like an old lady. I gained nothing but trouble from this swap, and it was very expensive. I should have stayed stock, rebuilt what I had and trusted that the GM engineers knew their stuff. The shop that tossed out my leaking Edel 1406 and installed my Roch Qjet had to replace the “cheap” choke + some linkage, and the Qjet builder wants me to feed only 4 p.s.i. to the carb which in practice means a fuel pressure regulator, something I’d rather avoid. Meanwhile, I can sit in my ’78 with stock 305 and dualjet, and enjoy a carefree drive. Enough of my frustration!

My Qjet is from SMI (Sean Murphy Induction). It is level 1. I waited 3 months for it, and it cost me over $500.

I hope that someone on the forum, smarter than I, will offer you useful advice. Good to hear from you and best wishes.