Water Pump Suggestion

Have 1965 Dart with Charger 273. Radiator was leaking so I pulled it out the other day and took it to the radiator shop for repairs. Checked the water pump and there is some play in the shaft so I am going to replace the pump. Anyone have suggestions as to where to buy a replacement?
Checked the parts stores ( Auto Zone, Napa, Advance, O'Reilly's, and Rock Auto) and price at all of them are within a couple of dollars. Who would you buy a water pump from?