I think it's easier to swap the drivetrain.
Also, know what you're getting into with the mechanical ones. The 1st gen has a weak pump, so you have to be careful not to kill it (bad fuel or lift pump failure are the major issues), however it is okay for cold starting with synthetic oil. Also, the first gen transmissions are generally pretty 'meh', the auto is not a lockup converter, and the manual is a Getrag IIRC. Most of them don't have an intercooler, which is a big minus. Don't jack with the fuel adjustments on them too much either, or use caution if you're going to. Also, watch for the steering box ripping off the frame (push-pull setup, junk), and rust or cracking near the spring hangers and fuel tank.
Also, they drive like something that was designed in the 70s, because, well, it's a 70s chassis.