Maybe I'm just fond of iron but I tell you what I think I'd rather run a set of Speedmaster Magnum heads after I do the work I do then to drop a set of out of the box sm aluminum heads onto anything.
I know that's iron to aluminum ...but, well... dried dog turds are lightweight too.
Smaller port that flows 260 with a smaller valve too boot...vs a larger port and valve that does 250 or about. The problem with a lot of these aluminum heads is they're all generic in the chamber and don't leave material that could actually help there and in the bowl. Just a toilet under the valve. Lol
They will make the power with work into them, not saying they won't. I'm saying heads with smaller ports flow with them.