'64 Dart questions

Hello all, I am new to the site and have a '64 Dart GT conv. with the v-8 chassis which I would like to retro a 360 into. (Original motor missing when I purchased the car). I have the orig. pushbutton trans(900 series?), does anyone know if it would be a good idea to use this trans (rebuilt)with a new 360, or would I be better off with a newer one? I sure would like to keep the pushbutton linkage, anyone know if I could get a kit to adapt it to a newer trans? Also, any suggesstions on a stronger rear-end that would work on this car? Any knowledge would be greatly appreciated!!!