63 Dodge Dart newcomer questions/advice

Hi everyone I just bought my first project car, it’s a 63 Dodge Dart 170 with a 225 ci /6 auto. I have a lot of questions and looking for some advice on working on this car. I’m still pretty new to working on cars so if I get some terms wrong, please educate me, I’m very open to learning new things. I want to keep this short because I have questions about my car. My goal for this car is not for restoration, I guess I’m going more along the lines with a ratty build, fun car idea, Ratty muscle cars, roadkill, etc. You get the idea. It has a lot of rust, but I plan on fixing some of the bad rust.

I bought my car as is for 500 bucks, I knew it was going to have some problems and missing things. So, I found out that the driveshaft is missing and I’m assuming since this is a push button trans, it’s a old style 904, with the ball and trunnion type driveshaft. My question is would it be more worth it to find the right driveshaft for this trans or buy a newer 904 trans that would fit a slip yoke?

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I've got a driveshaft with ball and trunnion setup from a '64 Dart - slant 6, 3 spd manual A903 - per this post, Slant Six Dan (Post #4) says it's the same length for manual or auto
If you want it, it's yours for cost of shipping (and, anybody got recommendations on how to ship a driveshaft?)