Which port do you add refrigerant to a 1971 plymouth fury 306 ac unit?

To add refrigerant to a 1971 Plymouth Fury with a 306 AC unit, you should locate the low-pressure service port, which is typically on the larger diameter tubing connecting the compressor to the evaporator. It is usually marked with a blue cap. Always ensure the engine is off and the AC system is properly diagnosed before adding refrigerant.