Which head/combustion chamber is better for performance? Speed master aluminum LA or aftermarket magnum iron head?

He’s told me probably 4 times and all I know is it was a better magnum head that was on factory crate engines and is no longer available. The short side excited my fingers. Kinda like a W2 only different.
Thanks, that was definitely the cast iron magnum R/T. They were a magnum style head with W2 influence. @Brian Hafliger at IMM is currently evaluating a set for me now. I’ll post what he finds.