Jaguar and Porsche have done the same for years. Check out a late '80s XJS.
Aluminum heads are tolerant of much higher compression levels than cast iron due to better heat dissipation.
Hemispherical, or semi-hemi heads also allow higher compression... something about flame front and burn patterns... beyond my depth.

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I suggest we solve high gas prices with environmentalists... unfortunately they don't burn well.
1982 300CD, 220K miles: This vacuum system will be the death of me yet! (OBK #26)
1977 F150 400 C6 2wd, 10.2 sec 1/8 mile with 2.75 gears.
1965 Mustang. Mostly stock... LOL!
2001 Ram 2500, cummins, 5spd, 202k miles.(girlfriends)