1. You'd either have an aluminum head that was so thin a baby fart would blow it apart,
2. Let me see if I can sum it up without typing a book.
3. The rate of change in increase of temperature of combustion is so fast, that the rate of change of temperature of the coolant can't accept that temp increase.
IOW's, no matter how fast the head materiel can reject or dissipate heat, the coolant can only take so much of an increase. And coolant accepts heat much slower.
And then, we can discuss how many BTU's the coolant can reject, at what load does heat dissipation become relevant?
4. For example, you have an 11:1 CI headed engine and cruising down the road, temp and load stabilized, and when most detonation occurs is right here...when you transition into tip in. The load goes straight up, the engine rattles and you either mash on it to get through it or back off the throttle to stop it.
Explain to me, with science, how an aluminum head can conduct heat so quickly as to remedy that.
I can also tell you this observed fact. Detonation almost never occurs at WOT. Almost never, and to get that your tune up has to be so jacked up that nothing will fix it except correcting the underlying issues and head materiel won't do that.
Low RPM, high load detonation is the real enemy, and an aluminum head ain't going to fix that.