Well, I'm new to the Holley carb world, so any help would be much appreciated. Setup is in sig, using a 700 CFM double pumper Holley carb. Whenever I am either stopped or at a steady cruise, if I nail the gas hard to the floor, there is a serious hesitation. I hear the air sucking into the engine, but nothing happens. After about a second (maybe a little less) it finally kicks in and the car hauls ***. I get between 8 and 9 inches of vacuum in drive at idle, and I have a 6.5" power valve in there. Do you guys think I would need a bigger power valve, or should I change the accelerator pump? If it has to do with the pump, do I just change the squirters or what? I really don't know jack about Holleys. Would you go bigger or smaller....I'm guessing the transition into the WOT circuit is lean. Any help would be greatly appreciated. Thanks.

 

my guess is when you step on it you're going to atmospheric and the vacuum goes away. power valve would be my guess, also you may want to reduce the amount of fuel.

 

Try a bigger squirter on the primary side to start..then try out various pump cams.Your PV is right around what you need.

 

question. is it immediately when you hit the throttle or goes falls over then goes again say within a second? power valve should be correct for 8-9" vacuum. make sure the squirter shoots fuel as sson as you move the throttle also. that would cause it to fall off then take off. if it's the second way then move the pump cam to position #2 look where the accelerator arm touches the primary throttle shaft. there is a cam with a screw in it. should be in the top hole (#1). move to #2 gives a longer squirt.

to change the squirter all you do is take a phillips screwdriver and change it out. i used a 31 squirter in mine. yours should be a 28. also i used a 50cc pump. the 700 is a 30cc pump. again more fuel.

 

It happens immediately when I hit the gas. Thanks.