'73 Duster help

I just bought a Duster and I've got no idea where to start. It was completely disassembled by the PO and that's how I got it. It's a base model 225 /6 automatic. Any info would be appreciated. What would be the ideal motor/tranny setup? It had factory ac I believe but some of the aluminum lines were cut off so I'm not sure if I want to put it back in. All the body work has been done and is perfect. I haven't found the fender tag but it could be in one of the boxes I got with the car.