Holley too big?
Thread Starter
Instructor
Joined: Aug 2007
Posts: 131
Likes: 0
From: Madison NJ
Holley too big?
I just picked up a 1970, C3, 350 with a 780 Holley List-3310
The car run very rich. The car has side pipes so it's bad with the windows down.
Is this carb just too big for a 350 or can it be tuned to work.
The car run very rich. The car has side pipes so it's bad with the windows down.
Is this carb just too big for a 350 or can it be tuned to work.
Le Mans Master
Joined: Dec 2003
Posts: 5,727
Likes: 38
From: Fremont CA
Get a LM-1 wideband meter and set you fuel mixture to a proper ratio. You power valve may also be blown in your Holley, float heigths can be too high causing a rich idle. Get a book on Holley carbs and read a little on the subject or go to Holleys web site. You can use a vacuum guage to set idle mixture by adjusting idle mixture screws to highest vacuum reading for "ballpark" correct AFR. Start with mixture screws about 1 1/4 to 1 1/2 turns out from bottomed and go from there. Adjust one side about 1/4 turn then go to other mixture screw and adjust it as you progress and idle vacuum is raised you may have to close the throttle blades of the carb (should idle around 800-950RPM with a street cam in a SB Chevy.) The final tuning can be 1/8 turn adjustments untill everything is close. One last caution: several other factors can effect idle mixture such as ignition timing, motor condition/specifications, intake manifold leaks, vacuum system leaks, ect. Hope this helps you out.
