LA318 Edelbrock Magnum v RHS LAX Heads
When I first got my Dart, I had it inspected at a local hotrod collector's garage... Both Mechanic and Tow Truck driver were "ol' school gear heads".
I told them I wanted a Daily Driver that I could be proud of bringing once in a while to the track. They both told me that, since i'd be mostly on the road, I'd be better with an Iron head... They handle the heat way better but aren't as performant as Aluminium heads.
Both heads you've mentionned are great. It all depends on what part of Street/Strip your balance is going to be... Street : Iron / Strip : Aluminium.
My own Dart is gonna have the Indy/RHS LA-X head...