I would go with the 750 but you need a mechanical one.you dont want a vacumm one.put 6.5 power valve and run 72 jets front and 82 rear and it will be very close to what you want.This is just what i would do.If you are going to drive it on the street a 650 will be fine. its just a opion thats all good luck.
well i guy wants to trade carbs, this is his carbs part number holley 3310 750 4brl vac. sec though. should i trade? he is willing to give cash with it. the carb is still on his truck and runs good. but i was told not to get a vac sec