My '71 Scamp 5.9 magnum swap.
I have heard too many people referring to lock up as OD because it drops 200 rpm when it locks. Even heard a guy with a a500 saying it was a 5 speed auto....
Magnum MPI fuel pressure is supposed to be 44#. They do ok with 40-48# but thats about max. The regulator is not internal, its mounted on the side of the factory fuel rail and is controlled by vac signal from intake port. Super easy/cheap way to use the Tanks Inc pump on a Magnum. They used the reg up until they went to single fuel line system with reg mounted on top of pump which was in tank. All early Mags with duel line system have a reg on rail.