Iron vs. Aluminum Heads: A Study of Heat

On this episode of Engine Masters, presented by AMSOIL, all else equal, which will make more power, an iron head or an aluminum one? Aside from the obvious weight savings, does aluminum's ability to shed heat help it make more power? Or does the iron head's heat retention promote cylinder pressure and therefore more power? There's only one way to find out, and that's right here on the dyno.