76 Duster Overheating at idle

First, "WHAT" is hot? Give us a number. Secondly, lets get some pictures of your fan and how close it is to the radiator. Also, what thermostat do you have?

One more little tidbit. These overseas radiators have NO consistency whatsoever. You may have a good one and you may not. Get an infrared temp gun from harbor freight. Get some readings at the thermostat area. Post those numbers. Shoot the upper radiator hose at the inlet of the radiator and at the bottom hose at the outlet and post those numbers. That will tell us whether the radiator is doing it's job.