Those heads and a 400..Sure would be fine with proper cam, carb, intake and rear gear selection.
If you do not have an intake yet, a 4234 or 0140 Pontiac cast iron would do (stay away from later egr) also a 750 q-jet (or equivalent) A Comp Cams revised Pontiac grind would be recommended.
I would wait on cam until you know for sure what rear gear you would have.
The motor with those heads will be up there in compression, so you may need to blend fuel.
Si Vis Pacem Parabellum
1967 Starlight black PMD Engineering 400 Auto 1968 Alpine Blue 400 4 speed 1968 Verdoro Green 400 HO 4 speed 2013 1LE 2SS/RS Inferno Orange Camaro.
