what are you going to use the car for
just drive it, all street use
street and strip
street strip and track.
it all come down to how much fuel you want to use.
Holley`s ( 650 to 780 DP centre pivot ) are good old fashion carburettor's . you can tune them very well but they really only work properly in narrow rpm ranges.
say want it to run hard , 4000RPM to 5600 RPM and set it up for that RPM it will run rich below 3800RPM
Be careful if you contemplate a carby above 780 in a street engine in a Double pump mechanical set up.
as I remember it the Holley works on 4''Hg across the venture. opening the throttle at low RPM can give you a major hesitation, with a engine tha has to much cam overlap, and larger carby, not a good thing in traffic around town.
what's wrong with the Rochester , set up correctly they are on of the best on the market.