I didn't know there were any Dodge humpbacks left to be resurrected! They were so hot in the '70s.

Both states with which I am familiar have a bonded title program. It is necessary to get a bill of sale from the seller, I'd suggest getting it notarized. Get his name, address and driver's license number at minimum.

It really helps if you can find a VIN or serial number or whatever the manufacturer was using at the time.

Then you take all this plus a few hundred dollars to the MVD and be patient. Bonded title FAQs are all over the internet.