54 Savoy project

For a first build, i would much prefer a 360 with a 518, compared to a big block with a 727. I think the smaller (physically) motor will be an easier fit, and most people are used to overdrive transmission engine speeds on the freeway. Unless you plan on changing the rear end, i think you will find a pretty stiff gear in the back, and you will be happier with an overdrive, auto or stick. The overdrive, and the smaller size is why i would do a small block, a 360 roller block if you can find one.