Thanks for the picture info. I went with World Products, Dart II cast iron heads and 2.02 ss Manley valves. I upped the ante quite a bit with a fairly radical Comp Cams roller cam with Hydrolic lifters.
I have an orginal 1966 3 duece intake. For performance I would have just as good or better with a big 4 barrel but after "the look". Men and small boys smile when they see it.

Can you calculate carb size by multipling 347CI /min by desired RPM to find how many Cubic Feet per minute the carb needs to flow? Does it come out 500 CFM?