340 in early abody

Going to do a mild 340, mildly ported jheads, looking at the voodoo cam or something compareble, I have a early 70’s. 904 no converter yet, I picked up a few 340 motors and 489 83/4 posi unit for a hellacious price so I want to run that rear end for atleast while but the gears in are like high 4,s don’t remember specifics but they were big, the Trans is supposedly good but would hate to show horn everything in the car to find out otherwise so I may have it build, with the manual valve body have heard u need a cooler, other than that anything outside of the norm,