I have a 40 1/2 ton with a small block chevy in it. It runs and drives great, but to be honest I am really tired of boring small block chevys in everything. I am in the middle of building a 39 1/2 ton with a 1963 Buick 401 motor(nailhead). It is taking a lot more effort to make it fit nice and a lot more money, but it looks really awesome and it is really different.