Vacuum sec carbs certainly have their place, but you do not need one with those inches and gears. I would suggest a DP, but they are usually very rich in the transitions for the street.

What type of intake? Dual or single plane? What is more important, top power or driveability? Can you tune the carb or will it be run without changes?

And I would be surprised if a 470" will pull all the way to 6,500 with those heads and a 240ish cam. My 500" has ported Eddies and it is done by 6,200 or so with cams in the 260* range.