Heater blower motor, Are motors & housings interchangeable? Options

[zonedoubt]

The heater blower motor in my '74 is toast. I bench tested the motor w/ 12VDC and confirmed that the supply circuit is working OK. It's probably the original motor and finally kicked the bucket from constant heat exposure in the engine bay.

The type of motor that is in there is the single output tube with a Y-adapter. Two hoses come off the Y and go to the two J-tubes on either side of the engine bay. I know that on most 74's, the motor has one output and that the passenger side J-tube is usually capped. This car was probably set up to output more heat to deal with the cold Canadian climate.

My question is whether the motor from the earlier 2-output fan blowers can be easily removed and fitted to the housing on the later style blowers? Alternatively, are there any other motors (Porsche or VW) that will fit?

Or...does anyone have a good condition working motor they want to sell? It could be the single output type since I could simply swap the motor the Y-adapter.