if you use a simple math formula. it says to use a 500cfm carb for a street driving application and a "650 for all out racing" the 600 is more suited for a 350 daily drivin street application
considering most came with 500cfm 2 barrels that ran great. the 600 is a better choice for this set up IMO and most engine builders will agree.
and the cars that came with 750's had 4 speed manuals in them or were muscle cars with soild lifter cams