Which harness? Engine side or dash?
I have mixed and matched wire harnesses of these cars over the years. Mostly it boils down to small things. In your case, the 72 model used different terminal ends for the front side marker lights. The 71 used a male/female plug similar to what Mopar used on the electronic distributors. The 72-76 used a rubber end socket with a small bulb in it. I believe that the grille mounted turn signals had a different terminal end as well. There were other changes. In some years the starter relay was on the firewall, others it was on the inner fender near the battery. The Voltage Regulator also moved around from beside the bulkhead, to the other side near the heater fan motor. Sometimes the VR was close to the alternator on the inner fender. Who knows why they kept moving it.
Sometimes there will be different wires in a harness, wires that you have NO use for. I've found that emission switches, spark delays, etc also varied from year to year.
