A 4.500 crank fits in a tall deck with stock cam location, and low decks are the same, as far as that is concerned. If a larger bore spacing is easy to incorporate and do either, then you have the best of both worlds. A 4.500 x 4.600bore is 598"...
Now that would be NICE in a low deck with some TS heads.. I would bet that it would be 1300hp..