Yes a MOPAR site... so MOPAR is the recommendation. The 440 should make 350-400 HP with a cam swap and good manifold.

As I remember, the Studabaker would have originally had a very small small block. Would a BB fit? How about suspension mods to carry the weight? Personally I would look for a 360 or 5.9 Magnum... and stroke it to ~400 CI if you want more. Magnum manifolds are pretty good.