its all about booster signal. that combo would probably run fine with a dominator, it has so much signal its crazy. if it were mine I would put a vic jr and a good 750 4150 like a quickfuel or AED and watch it go 11s. we had issues three holley 4150s with a 10:1 358" Cleveland headed Windsor with a big intake and a decent sized flat tappet cam. it wouldn't even run right with a new 650HP. the 650HP, a good known 750 HP, and an 830 that ran good on a 347 with small heads all had a stumble out of the hole on the secondary side. all these carbs went 7.30s@95 in the 1/8th. then we unhooked the secondaries on the 830 and the stumble went away. the car went 7.20s@93 like that. then we bolted on my AED 750 HO modified, adjusted the idle and made sure everything was adjusted correctly. the car went a 6.88@98mph with it setup the same as it came out of the box from summit. so there is a little more to carbs than just having the 'right' cfm rating.
im gonna have to disagree with ya. its about finding the right size based on displacement, induction cross section, compression, camshaft, vehicle weight, gearing, and converter.
http://www.aedperformance.com/tuning-tips.html
The OP is talking about a mildly modded engine. You are talking a different story. Put it in context.
After all the OP's 600 cfm took him to 5800 rpm and 12.86 et in the 1320'. You think he would do better with a 750 cfm(considering everything else the same) ??
Dominator? What? Gimme a break....