I have a 57 Chevy 2-door sedan, daily driver, with the original 235 six and a three-speed tranny.

The 3-speed is tolerable, except that I keep hunting for 4th gear while driving it (old habits die hard) and also it sometimes jumps out of third when I'm cruising on the interstate.

I'm looking for some options on replacing the 3-speed with a 4- or 5-speed. I want something simple -- I'm not a novice, just don't want to turn this into an R&D project: already got plenty of those!