From Hughes site, BB 84cc rpm's flow
[email protected]" (your cam lift) or at least the head they tested showed that. If that is somewhere close to what you have that should be enough for 450>480hp@around a true 10:1CR with a good sealing short block/tune and good enough induction.. They go on to flow
[email protected] and then fall back to
[email protected]. to raise things to 500hp+ is poss with those heads but you would need more cam/carb/compression than you currently have.