By the time you get a 906 or a 452 set of iron heads ready to make 500 horsepower, with a mild cam (or a radical cam for that matter), you could have bought set of better aluminum heads. Well, unless you own a head porting shop.
I did a 440 with 906 heads. I had about 1,200 IIRC into a fully ported and blueprinted set of 906's. Keep in mind this was 20 years ago, so add for inflation. I had dome pistons with a static compression of 10.5:1. The cam was [email protected], .557 lift on a 112LCA installed 2 degrees advanced. The timing was 18/36 all in at 2,500. That engine made 467hp and 514tq with a crap intake and too small a carb. Close to that magic 500 number.... That engine ran on pump premium.
That engine also ended up leaking in 5 out of 8 cylinders and needed to be torn back apart and fixed with epoxy.
Unless your build requires iron heads it's tough to beat aluminum heads. Especially when they can be bought for 1,000 a set...assembled!
