your 408 with iron heads IS respectable at 430 hp. But it is under headed for any future big hp gains.
If I'm building an engine and need to sink money into refurbishing heads, I'm moving to aluminum for a few more bucks.
Completely agree. I had them and put $300 into them freshening them up. If I had to acquire a set of heads, 100% agree, buy a set of aluminum.
I did that myself and stepped up to CNC220 heads from BPE, Bloomer Performance Engineering out of South Bend. Rod is a great guy, he teamed up with Brett Miller and Bischoff on the CNC program and mill work. The heads will support more power than I am putting to them but I won't have to upgrade heads when I do upgrade the short block and upgrade to solid roller cam.