E headed 455.

I have had both RAII heads on a 400 and 72 HO 455 heads on a 455 (comparable flow ratios adjusted for displacement).

I do agree that iron is better if the heads are done right and complete and you do not have to spend $$$ on correcting someone else's "work" as RA II heads, over 45 years, typically have issues. If they don't, they are $4000 plus..just for heads.

All things being equal, would I rather have iron or aluminum? If I don't have a RA II car, aluminum. If I don't have a RA II car and want to race in a class, RAII heads. If I want a performance gain, heads ported from Butler...with warranty...E Heads all day. A lot more flexibility with E heads.

You can buy a set of E Heads, ready to bolt on from Butler that will match the performance of RA II heads at half the price, all in. Heck, I even saw a set on a Firebird at the Nationals 3 or 4 years ago that had E heads that were modified to look like round port heads. I had to look twice.

Being said, Yes, I am a purist...but as a purist, I have limitations.