While I am a SB guy, in the long run you will be better with the BBC. The converter should be fine, it is more a function of cam duration than lift, but in reality what RPM range the engine makes power. The 433 should have in the neighborhood of 650 HP and run at least mid 8's in the 1/4. Used BBC dragster headers should be easy to find in good shape, try to stay around 2 1/4 " primaries. The 377 could run close depending on head prep and cam, but will have to turn up the RPM's more and need a little more converter.