To buy or not?

Hello everyone, I know I haven't posted very much but I would like to ask a question because most of you are way smarter about these cars then me.

So I have found 2 cars that I am considering to buy. One is a 1972 Dart with a 318 that runs and drive pretty much rust free (which is hard to find around here) but is kinda plain jane. Has a bench seat, a column shift auto, ac. power brakes, power steering but thats really it. The other is a 1973 Dart Sport with a 340 but it doesn't run and the guy doesn't know how long it has been since it was started. It has been in his family for all its life and the extra features are unknown on it. The sport is a higher price then the dart but the dart is pretty much ready to roll. So what would you guys and gals do?