Just got this 1966 Dart GT
I bought them second hand/ new.
They are mustang rotors that Ram does some machining to for the inner seal to fit.
They’re 4.5 bolt pattern. They use stock wheel bearings, National A2 & A6. I bought new bearings, rotors came with new seals.
Instructions say Mopar used two different venders for the dust shields, and depending on which ones you have you may need to open the center hole for inner hub/seal area to fit into it. Of course I was lucky and had to get out a grinder. Swapped them in a couple of hours. Swapping rear axles tomorrow.
….I think the hub gets machined so the rear race/bearing gets sunk in a little deeper also.