Mounting a muncie to a small block mopar??

The 833 4spd was made by New Process Gear Division. It sounds like all you really need is high gear for racing and first gear just to get rolling, if thats the case I would find a either a mopar A230 (non syncronized 1st gear) or A903 (fully syncronized) three speed. If you really want to get crazy you could remove second gear from the transmission to get rid of a little rotating weight. I think a 4 spd would be overkill if you're going to be in high gear all the time.