Best head for the money??

I'm looking for some information or suggestions on which set of heads to use. My son and I are building a 383/727 for a 72 Swinger. We have a set of 71 906 heads and a set of 66 516 heads, we would like to be around 9.5 CR and 375-400 HP and run on pump gas. We are talking about using a mild cam around .488 lift. I don't know what cc the 516 are, both heads have 2.08 intakes but the 516 have 1.60 exh. compaired to 1.74 for the 906 heads. It has an 8 3/4 rear with 3.23 gears and will mainly be driven on the street. Whats your opinion?? Thanks