Hey Tony! I tend to agree with Rukee and Tripower. I'd stick some nice 400 or 455 in there.

Mine was the stock 400. It's beautiful! I'm getting the body work done soon, so I drive it as much as possible. I tell ya, there's nothing like the feel of that motor...
Check out Ames Performance and Performance Years online and they'll send you a catalog of all their parts. You'll find pretty much everything you need to fix that ride.
And by the way, thank you!
Linda