390 double pumper vacuum

skinnysteve72 said

Switched out this carb for a different one , still dealing with high idle (2500+) got it started and running but once it’s in gear it dies

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1) That 390 would've started out with screw-in Hi & Low/Idle air bleeds, and power valves. But since it was a NAPCAR legal unit for restrictor-plate comp., the air bleeds & the PV passages could've been employed to sneak air around the venturis, " Witch Doctor" work as posted above. It's a geat carb for somebody other than You..lol..
2) If an entirely different carb has resulted in a 2,500rpm idle, You either have an air leak, the throttles are on a fast-idle step, or the throttles also have idle-compensating holes drilled in them. The VS Holley 600 had those depending on the list#, so You'll need to verify the presence or absence of these items/conditions.