You've got to build your bottom-end on paper before you choose heads. Deck height, piston design, gasket thickness, cam choice, desired fuel, RPM range, desired CR, power desired all play a factor in which heads to use.
I like the camel humps, they have good flowing ports, decent CRs, (double check that) and larger valves. However, Ive seen many a set of older Power-Pac heads (small valve 283-327) passed off as Camels. Check the casting numbers and valve size to verify. Have them magged for cracks. Some early Camel Humps don't have all bolt holes for belt-driven accessories, or you might have to use period-pieces to make it line up.
The 305s may boost the CR some, but check valve sizes, chamber design, bore spacing, before buying. Make sure ports haven't been 'hogged out' during porting.
Ive heard good things about the vortec and fast burn heads. The newer designs were computer modeled & designed, but I don't know how well they work with a carb.
The key to head selection is to know what they're going on. You can't just stick a set of heads on a motor and expect magic.
good luck
chip
