Performer RPM or Magnum Heads

I would go with the regular RPM heads, non- magnum. WHY?!?!? Better flow numbers under curve on a OOTB condition. Screw the extra lift with the 1.6 rockers on a older block. You can have that ground in the cam. After that, ask a head port which one does better after they get done with it.

Then again, I wouldn't touch them next to a set of big port comandos.