Get a set of used fast burn heads from any of the dirt track guys (even racing junk will have them)
1.5:1 ratio aluminum roller rocker arms
2.00" Intake / 1.55" Exhaust valves
And get a 604 crate cam
Cam lift: .474" intake / .510" exhaust
Cam duration @ .050": 208° intake / 221° exhaust
112°...