This is my first post after trolling the forums for a few weeks. I am thinking about building up the 327 in a '66 Bel Air station wagon that has been siting in a barn for 20 plus years. I am debating on weather to use some iron vortec heads or aluminum heads of some sort. From what I understand aluminum disipates heat better so you can run higher compression and are also lighter witch might also help mpg. Or would the heat holding abilitys of iron heads but low comp. ratios do more to help mpg.