Budget Aluminum Heads
I would wait for speedmasters black friday sale.....and try to get their Victor copies, cnc version, bare. (and MAYBE get the sm rockers for them too, good rockers from Hughes or Harland sharp are expensive!). I would guess they are capable of 150hp over stock iron 67 heads.
Sometimes their black friday deals can be amazing, IF the have something other than Ford and chevy parts......