More Holley Carb Help Needed!!

[baypally208]

I just purchased a 385HP crate engine to replace my 250hp crate engine. Both 351W's. The 250HP had a Holley 650. The 385HP came with a Holley 750. Both DP's w/Mech Secondaries.

The previous owner of the 385HP stated that it idled really rough.

This is no lie. Anything under 1K and it shakes the car apart.

Additionally, there's a huge flat spot in accelleration and the mixture screws have NO affect on idle whatsoever. I suspect the 750 carb's had it and needs to be rebuilt.

As a test, we dropped the 650 onto the 385 and it runs like a dream. Unfortunately, the (*&*&O* 650 is slightly taller and won't clear the hood with the big oval "Cobra" air cleaner installed.

Any suggestions besides a new air cleaner? Is there a shorter version of the 650DP? Anyone?

PS: I read the other "Holley carb help" thread and Holly seems to think that the 600 or 650 is more correctly suited to the 351 than the 750. See http://www.holley.com/HiOctn/ProdLin...FMSC/FMSC.html

Thanks Guys!

-Drew

[Bill Wells]

forget the looks of the oval air cleaner. if the other carb is better, then get an aircleaner that fits under the hood . ...or have the other carb redetailed/rebuilt as something is amiss with it. an aircleaner is usually cheaper than a custom redone carb. a basic rebuilt carb however is probably a wash in cost vs a custom redone carb. bill.

[baypally208]

Thanks Bill. I'll try rebuilding the 750 first.

-Drew