Ok well i got a fuel pump (holley blue) and i have it regulated at 6.5 psi right now. My setup is,(in a 1980 toyota corolla) 12a w/ upgraded apex seals, holley 650cfm 4barrel carb., racing beat intake and header, and bridgeported motor. The car feels alot smoother normal driving now with the fuel pump but when i punch it, it breaks up. I do not have a tach at the moment but my best guess would be its breaking up at about 5/6k rpms when it wants to make power since its bp'd. What do you guys think is the problem with it just breaking up.

 

the car basically will stop goign up in rpms and sounds like its choking or something.. feels like you hit a brick wall