NOTE - since this posted at the top of a new page, be sure to check the previous page if you are looking for OEM installation schematics for 1960-63 heaters.
In response to the earlier questions asking about late model heater motor options, I swapped my original for one out of a Pontiac Fiero. The main thing I was looking for was one that rotated in the correct direction. At the time it seemed the only models I could find were those in S10 pickups and the Fiero. The advantage of the Fiero over the S10 is that they are all mounted in the trunk, so they are clean and look like new compared to one that’s been mounted under the hood for a couple of decades.
The heater case required some minor trimming, but the much larger plastic fan fit into the case without modification. The motor itself is the newer permanent magnet design. On high speed airflow is about twice that of the original fan and motor. The rubber hose is presumably for motor ventilation. It doesn't go anywhere in my installation, so I just pointed it downward to keep dust out.
I don’t have any decent photos, but here’s what it looks like installed on an economy heater:
