What if your carb is too big?

[tdsmith]

Ok, I've been trying to track down a mysterious problem with my car since I got it. For some reason my power drops off really sharply @ 5200 RPM. I've talked to lots of people with different opinions. Some of the most common was too small of a fuel pump or the fact that I had a single plain intake. Both have been rectified. I now have an Edelbrock RMP Air-Gap intake, Performer RPM heads, and now a Holley Blue fuel pump set @ 6 p.s.i. My question now is could my carburetor be too big and if so, what would the effect be?

Full specs on my engine:
351W
KB181 pistons (22cc dish)
Edlebrock Performer RPM heads (60cc)
9.1:1 compression ratio
Edelbrock RPM Air-Gap Intake
Holley Blue fuel pump (6 p.s.i.)
Holley 750 CFM double pumper carb (#4779)
Cam custom ground (270 285 duration, 220 230 @ 50, 507 intake 532 Exhaust lift, 110 lobe center)
New K & N air filter
Distributor set 14 intial and 36 final advance


I've talked with the guy who built the engine for House of Cobras a few years back and he doesn't understand why I'm not getting the higher RMPs, so I'm turning to all of you. I would like to get to
6500 RPM if possible. I was on Holley's website and according to
their formula (Engine size * max RPM/ 3456 = CFM) a 650 carb would be plenty for my engine. So my first question is could the larger carburetor be part of my problem? I've had it tuned for air fuel mixture, but could it still be causing a problem? Should I buy a smaller carb?

Do you have any ideas what I need to look at? I'm technical enough to put an engine together on my own, but not to know what things I should and should not try for this specific problem.

Thanks in advance.

Troy SPF#578