I am switching from a 800CFM marine to a Holly 830 (chokeless race carb) on a HP500 (9.3 TO 1, 108 INTAKE LOBE CENTERLINE).

Should I start with the same jets ??????
Primary port 81 starboard75
Secondary port 89 secondary 93
6.5 powervalve

The secondary metering plate on the 800CFM Marine was leaking fuel into the intake from the bowl????
What would cause that????????

THANKS!!!!!!

Try changing the needle and seat. And put on new gaskets. Check power valve gasket too. Easy to do for a few bucks.

Dan

I would think the jets are close but someone here has a set up closer to your can probable better answer.

If it was me I would throw in a new power valve while I had it apart.

DanB

Leak is in just above the butterflies in the secondaries, no secondary power valve or idle circuit

I'll double check the gasket this afternoon.

I run 85/96 in my std Holley 800cfm. 731 Crane cam & CMI headers. Merlin intake.

RickR,

If you are running the Holley #9381 830cfm, you have two power valves. Your jetting will be very close on the primary and secondaries. You will have best results with the staggered jetting, although it will be different than than the 800.
I might ask, why did you change from the 800 to the 830??

anybody now why the stock jetting is so stagered on these motors from side to side.it just seems a little strange.

It evens out the air fuel mixture to each cylinder.

THANKS EVERYONE!!!!!!

FIXED!!!!!

The idle bleed hole in the top of the main body was clogged. Causing fuel to siphon.

She's purring like a kitten :yes: