If it's a good running engine as is I would get the 380/360 crate motor cam/valve springs and a 4 barrel M1 carb manifold with a 750 carb, the M1 has the offset T-stat and bypass hose to use all the stock magnum front dress.

Put a good 9.5" converter in the 904 and run 3.23-3.55's depending on how tall the tire is.

You can run the EFI also but it will require a new fuel system and the computer to run it, the build will be different as well- it will need a smaller cam and a good set of heads so the PCM doesn't freak out.