I believe on a 72 Dart with no PS there is a single belt that hits the water pump, crank pulley and alternator (where the adjustment is). On a PS car there is a small single belt that hits the crank pulley and the PS pump (where the adjustment is), so 2 groove crank pulley, and the PS only belt would be all that is needed. There's no A on this car, right? If there is that a whole 'nother kettle of fish.