the truck is running really good. pretty much a stock chevy 350 with a victor jr intake and 750 vaccum sec carb. my question is it runs like a champ but if i punch it from a stop or slightly step on it from a roll it falls on its face for a second kinda like cutting out then gets with the program. i have played with pump shot on the holley but nothing really helps. the timming is right what else could be causing this stumble stall to occur and how do i get rid of it. this truck is supposed to be going to the track and i want it to run right when it gets there.

Maybe its the Victor Jr/big carb for a stock motor...if you nut it at like 3,000rpm's does it respond quickly? What is your timing curve like?

i notice at a steady cruise at about 60 if i press the pedal it will bog real quick and then start going. the slower i go the worse it gets. i don't think the intake and carb are too big. yea i am giving up some on the bottom end but in a 1975 luv it is not a bad thing. could the carb be jetted to rich/lean? the pump shot doesn't seem to make a difference.

what can i try to find a answer?

CB Have you ready any books on tuning the holley carbs? lotsa info there. I would say if the motor it stock it would probably give you better response with a smaller carb, like a 650. with the carb you have now I suggest getting a vac gaude hooked up and use that to tune your Power valve. Another common area to "adjust" throttle responce is to install a stiffer secondary spring in the vac diaphragm if you are goping to stay with that carb. Lastly (or firstly) check the pump arm for propper adjustment. Seriously I dont know you or your skill level but if you are serious you'll get a FEW books and read all you can!

Good Luck
Milan

Where is your VAC adv hooked to. you might try hooking to a diff source.

Sounds like your secondaries are opening too quickly, but it's odd that the pump shot doesn't have any effect. You could try disabling the secondaries if you don't have a spring kit to experiment with. With a stock 350 (what year/rating?) you'll probably have to slow the secondaries down.

Remember, everyone with timing problems thinks their timing is ok to begin with - experimenting with it is cheap and won't hurt anything.

I have struggled with the same problem. I purchased a Holley book and read it three times. Make sure your idle mixture screws are set correctly. Confirm your float settings. From there, I tried different pump shot cams, jets, shooters, and power valves. Hook up a vacuum gauge for the correct power valve. I ended up with more initial timing, different pump shot cam, higher power valve and two sizes larger jets. Change one thing at a time and keep a record of each change. It is easy to get lost.

750 on a small block,, Stock converter maybe 3.08's graemlins/waving.gif ? Way to big for that little motor. Normaly a 650 is the way to go and if it's a auto car Vac secondarys with heavy springs.