From what I understand, modern aluminum radiators require a special
antifreeze that's not your typical Prestone green. In fact, I think it's orange, but I can't remember the special ingredient it contains. Distilled water is recommended too, instead of tap water due to the mineral content of tap water.
Also, since you MAY have two dissimilar metals, aluminum heads and cast iron block, so it's highly recommended that a sacrificial anode be used.