Quote:

But don't take it from me. Here:
Iron vs aluminum heads




Not really relevant since they used a much more aggresive cam that would help to bleed off some cyclinder pressure as was suggested by previous posters.

Check out KB pistons site. They have tech article with recommended compression ratios and sure seem to believe there is a difference between cast iron and aluminum heads. I'd believe KB before I'd believe some mag article done using a long duration cam.