Looking for 70 Dart blower motor

Can anyone tell me where I can find a replacement non A/C heater blower motor for my 70 Swinger 340? Does anybody rebuild these? Mine squeals on lower speeds.
Temporary fix would be to drill a small hole in the outer casing where the shaft is and squirting some electrical motor oil in the hole. Then cover the hole with tape or whatever! Used to do this quite regularly. Just a thought.