Quote:

If you went from an iron head to an aluminium head without any other change you effectively lost compression. The aluminum pulls more heat out of the chamber .



Not true. It ALLOWS more compression for a given octane, it does not REQUIRE more compression. Seen a couple tests with identical ports and chambers in iron and aluminum heads and no difference in HP but the timing could be advanced farther before pinging with the aluminum heads.

I am not causing global warming, I am just trying to hold off a impending Ice Age!