1974 dart 3 on tree

IMO those 903 transmissions are a POS. If you just putt around with it, it'll work but they won't handle any kind of horsepower. The 230 is a much better 3 speed but it was made for a floor shift car. I'm not sure what you'd need to do to get it to work with your column shift linkage. The 250 3 speed is also better than the 903 but not better than the 230 but at least it was designed for column shift vehicles. The 745 is a pretty good one too but they are not too easy to find anymore.