302 heads

i would rework the heads you have, the later model heads have bigger combustion chambers and you'll a lot of compression, easily 1/2 a point maybe even as much as a full point. the valves from the smog heads should fit in the bare set, i don't recall them changing the valve size between the 2 heads, they just drilled the thermactor passage is all. why not have someone do a mild port job on the good set while you're at it, nothing major, just remove the thermactor bumps and do a little cleanup