Don't know, Regs.... Guess I'd be for getting the old one out and see how bad things are first.... If it's the bearings or pistons, a bit of machine work, stroker kit, and a good set of aftermarket heads he could have the original engine with some updated power...

Otherwise, the 502 or 572 inch GM crate motors wouldn't be bad, seen a few of them installed and they make a good runner.....