[john6066]

i'm currently running a 780 holley dual feed on my ZZ454 engine. seems like it could use a bit more carb. any recommendations? thanks john
my car is a 69 chevelle with a 4 speed and 410 gears.

[Dan Orgill]

Tell us a bit more about your combo; stock ZZ454cam? intake, etc.

Just from a cfm standpoint, 780 seems like plenty.

[NickeyChevelle]

Originally Posted by john6066

i'm currently running a 780 holley dual feed on my ZZ454 engine. seems like it could use a bit more carb. any recommendations? thanks john
my car is a 69 chevelle with a 4 speed and 410 gears.

I would think that a 780 CFM Holley with vacuum secondaries (and a large air cleaner) would be ideal, but the Carb itself might need to be tweaked (jets, springs, etc.) to provide the response and level of service you're looking for. The formula to figure CFM is: CFM = (RPM x CID) / 3456. Which works out to 788.19 ASSUMING a 100% efficiency (sorry, but not likely). Any larger CFM and you'll actually degrade engine performance. Is there a Dyno shop nearby? THAT might be a better investment!

[smitty454]

Alot of people are running 750's on their 454s... Your carb may need some tuning or rebuilding but definately not more cfm.