Ok....when I crack oopen the throttle, i get real bad hesitation. Gradual acceleration is good. Even when I crack it open from a higher rpm.....dead spot! Doesn't seem to have any misses, and has plenty of power, except from a dead stop. Any suggestions?

My specs are:
Stock 396/325 block
Peanut heads redone
Crane 272 Hyd cam/lifters
Edelbrock performer manifold
Holley 4160 series 750 carb w/ vac secondaries
Hooker headers
Hei w/Proform upgrade

by the way...timing set at 8 btdc.decent idle at about 800-900rpm

I'm going to throw this out there but the more experienced people should really chime in, but I think you need a stiffer spring in your secondaries. Lighter springs cause secondaries to open faster and if they open too fast you will get a bog or hesitation.

Like I said let some more experienced people confirm this..

I would set the timing at around 14 degrees at idle and adjust your accelerator pump.

Just a thought do you have a Quadrajet and if so maybe your secondary flaps are opening to fast. That was my trouble one time when ever I hit it it would stumble then go.

i'm not an expert either, but have had this problem before and learned alot from these guys. i agree on timing and accel pump. don't know what you have in it but 8 degrees btdc seems way retarded. should be at the very least 10. i run mine at 12-14, it's perfect. also, if your accel pump is turned out too far, the shot of gas could be coming in too late. you can turn the nut on the top of the arm in, compressing it (clockwise) (using a wrench to secure bottom nut of arm while turning) to have the shot come in sooner. but only 1 complete turn at a time (i marked my original spot with a perm marker). you should actually do this at wide open throttle (with car NOT running obviously) so you don't bottom it out. don't go too far. let us know more of what you have and remember, TRY ONE THING AT A TIME. smile.gif

sorry, i looked again, you did include your specs, my bad. redface.gif

But when you adjust the accelerator pump actuator/spring tighter, doesn't it make the rod shorter? Wouldn't that make the gas come out later? What about adjusting the part that rides on the cam on the carb shaft?

What is your total timing?

Sounds like the initial is 8 degrees advanced.

Put a stiffer spring in the secondaries.

Bigger squirter.

Just did some tuning on my 402 with good results. First, check your total timing. You have to mark the balancer. Mine is 8" diameter so I marked it at 2.51" for 36 degrees. Time the motor for 36 total. You can double check the intial timing after. I also dropped the vac sec to the middle spring. The power curve and throttle response are real smooth now.