I am pretty sure I have a carb problem but have not been able to fix it. I don't know all the specs on the engine, I bought it from somebody then they disappeared. Its a 355ci-vortec heads-victor JR intake-with a Holley 750 street avenger carb. Timing is set at 10 degrees initial with 36 total with a max of 53 vac advance. It has 16" of vac at idle. It runs great unless you mash the throttle then there is a horrible dead spot, it will work through it if you are free reving, but if you are in gear it will stall. I installed a 8.5 power valve and it seemed to help, I also upped the squirters to a 36 and that seemed to help but it is still there. I am trying not to throw to much $$$ at it but maybe pump cam timing, or I was thinking of lightening the springs in the dizzy to get my advance in quicker. I am lost PLEASE help

 

Had the same problem running the 670 Street Avenger on my 305. Up the size of the jets and it will fix it. I don't remember how many steps larger I went, I bought a jet kit and experimented.

Dan

 

Jets will raise your fuel delivery across the board...not really what you need. Sounds like you are having a lean stumble when the secondaries open. Pump cams and squirters is the first place to look. Make sure the pump arms aren't lose. Also, bringing the timing in quicker can make a big difference. What are the cam specs and compression? I can give you some timing curve advice if I know those things.

 

I gave all the info I had in the original post. When I got the engine I did not get a cam card and I don't know what pistons are in it so I am clueless as far as compression. He said it should be between 400-500 hp, but after running it I doubt it. I have been thinking of changing the cam Just so I know what I have.