I realized after I posted my last comment that I wasn't thinking at all. First, the 474 and its little brother are good engines but very hard to find parts for it. When it comes to modifying & tweeking the engine's performance the Fords are a bit of a lemon. Where as the 359 Cummins has all sorts of performance parts available and it's still being produced.
Sorry! I didn't know what I was saying. I would keep the Cummins and build it up.
Thanks for the help.