I like Powell a lot, but it is a pretty big assumption that 330 cfm is needed for turning 5500 with 460 CID. That is more of a modern engine family way thinking for an LS, Gen 3 Hemi, or some Ford’s. Even on a modern engine platform it is a big stretch, that is well over 130 % VE.
One of the guys on PY recently dynoed in at 490 HP@5100 with his 461 Pontiac with 242 CFM D ports and 560+ lbs of tq. It was a Bullet HR and 236/
[email protected]”. With a single plane intake, more carb and bigger headers, it even would have made peak power at close to 5500 with those 242 cfm heads.