I have 4150 hp 830 cfm carb mounted on a 350 bored .60 over chevy. I have a super victor intake and a 2 inch Wilson 4 hole spacer. Heads are 200cc stage 2 world products. Im pulling about 5 inches of vaccum. The carb has 2.5 power valve front and rear 78 jetts in front and 84 in the rear;31 squirters front and rear. I have 2 problems, at idle there is fuel dripping out of the front annular boosters. It idles decent then when i put it in gear (350 automatic)it tries to shut off and dies. The second problem is that when i shut it off and let it sit there for about 10-20 minutes and i go take the bolts out of the bowls the bowls are empty.There is no fuel in them. It seeps down to the intake its like i have a leak in the carb somewhere. I tried everything new floats,gaskets,carb kits,(30cc)accelerator pumps,power valves.This carb worked fine until we started putting high octane fuel. If you have or had this similar problem your help is greatly appreciated. Thanks!

Welcome aboard thirdgen.org.

First, if you have power valves front and rear, you should be jetting square.

If you're pulling fuel through the boosters at idle, you have the throttle blades open too far. If you can't keep it running without opening the primaries that much, open up the secondaries a little more so that you're idling off of all 4 barrels (this should be a 4-corner idle carb).

The only place for fuel to leak on Holleys is external. If it isn't dripping out, it's boiling away.

Thanks 57kid im gonna try this but quick question Do you think there is a possibility the carb main body can be warped and its not sealing the metering block properly and thats why its leaking into the intake.?

Unlike q-jets and Edelbrock Performer carbs, there is no path for fuel to leak from the bowls to the intake manifold with Holleys.