Buick/DELCO part numbers
The original heater blower motor number was 5044342. Part number also shows up for all 59-62 Buick full size cars.
This was replaced with a universal DELCO motor no 5044399. It also shows applications for some models of Olds, Chev cars, Chev trucks from about 53-63.
The 59-62 Buick part number was 5044398 if the car has air conditioning. This one became DELCO universal replacement motor 5044400. Similar crossovers into othe GM applications as well.
These universal replacements pop up on eBay here and there.