[Dragncar]

Exactly what I was after.At 10.3 to 1 an engine with iron heads will ping with 91 octane gas with any kind of timming to make power and the aluminum headed engine with everything the same will not.Thus it makes more power.Sounds like someone wants to sell more aluminum heads.
The heat loss helps the aluminum headed engine not detonate.
If everthing is the same the iron heads will make more power.Timming,octane,heat,cooling,commpression throws a monkey wrench in the middle of it.Also,there is more power in gas that is lower in octane not less.Regular has more BTUS in it than premium.The stuff in a gallon of gas that makes it higher octane and gives it the ability to have a higher flash point just takes up space and does not burn.