450hp... that's nothing. A stock set of heads with mild clean up and a voodoo 268 hyd cam, Air Gap and a 750 with headers.
This made decent power with a small cam. Idled real nice with a Voodoo 268.
http://board.moparts.org/ubbthreads/showflat.php?Cat=0&Number=6780602&page=0&fpart=1&vc=1
You could get there with a set of RHS iron heads too. Save some money that way as well.
Your current cam choice is WAY too big for a 450hp output level.