The Saginaw four speed is plenty strong as long as you are not doing big giant holeshots, slicks, clutch dumps, dry burn outs. Here is the thing. They are a nice simple trans to rebuild. Yes you can get a rebuild kit for under a hundred, but spring for the better kits with the forged syncros. About 120. Also, and this one you will want to beat the bushes for, get a new pair of shift forks. One of the forks is used on both the four speed and three speed and so is pretty easy to come by new. The other is four speed only so that one is a little harder to do.
I paid 250 for my 2 groove sag. (3.11 first gear and its a ball, gets you going from a stop and no its not too low at all. Stock 50s three speeds generally were in the range of 2.94 first gears so pretty close). I paid 120 for the rebuild kit, a few dollars for degreaser, anaerobic sealer, probably another 140 for new forks, and a few dollars for paint. So I have like $550 into a fully rebuilt four speed. That is pretty hard to beat compared to the cost for a rebuilt muncie or BW T-10 or something of that nature.
Hurst still makes an installation kit if you want to use a Hurst shifter, otherwise the factory shifters will do. Its not a terrible choice for a transmission if you are trying to be careful with the money.
