Which heads wpuld be better?

70 Swinger, we specialize in 'new-by's' Some good and knowledgable people on this board. I agree with Rumblefish on the heads..only thing I would ad is to have the valves back cut 30 degrees while you are at it. Any year J or U casting will work and install the 2.020 intake valves. Try to keep the compression around 10 to 1. Good luck there 70 Swinger and keep us posted. Terry.