[Frank Messina]

The Ford Racing 351-385HP crate motor actually dynos at about 410 ± 5HP with a Holley carb. If you want to get up to the 450 475 range with that bottom end you'll need more head flow and a different cam. There are a number of heads that will get the job done but some like the AFR 205s will require flycutting the pistons because of the 2.08 intake valve. You will want something that flows about 280CFM or better at .600 lift. The factory pistons will take a 2.02 intake valve with no machine work so you might be better off sticking with the Ford Z heads. You'll need to do a good multiangle valve job and maybe touch up the port to get the flow you want at high lift but they'll fit and they flow better at low and mid lift than many of the others which helps to preserve good driveability on the street. The Victor JRs also flow well but use a 2.05 intake valve so you may have piston to valve contact. Not sure about that. With any of these I heads I'd use a 232-240 @.050 .566/.574 on 108° intake centerline with either 110 or 112° LSA. Lastly take enough of a cut off the heads to get compression up to 9.5 to 1 and you'll have a pretty potent combination that will still drive well on the street.
Frank