I concur.... 750cfm ain't nearly enough for racing. I would put you at least 950 or 1050cfm for that motor. We need to know more of your cam specs (duration, LSA, etc)... heads might be a little too restrictive but this will be a balance between how quick you want to go and how streetable you want to keep it. Judging between your et and mph I would say you will see a world of difference with a shorter (numerically higher) rear gear (4.30 or 4.56).... You can stand more lift (.600+) and duration (~270@.050) especially with 496 cubes but then you're probably looking at a higher stall (~3500). Do you want to go as fast as possible or do you want street friendly or somewhere in between? I agree more cfm in carb is first place to start... if you're serious then big cam, single plane intake and shorter rear gear will get you low 10's but not so good street manners. Really should have bigger rect port heads.

For reference I have 10.8:1 439ci 255/264@.50 .630/.630 110lsa single plane 850dp (too small) large oval heads but the wildcard is high altitude... 3300lbs 11.5 @ 117 best with 4.56 gear and 29" tire pump premium (should be ~10.8-10.9's at sea level)

-Chris