The heater blower assembly mounts under the passenger fender, taking fresh air in from the fender vent on that side and then pushing the air back to the under seat heater core by means of a long tube, similar in size to the dryer vent in your home. Since my car didn't come with a heater, most of this assembly was missing and I'd purchased more than enough bits earlier on to piece together what I needed.
So going through my box of heater parts, I picked through what looked like the best of the lot, and started disassembling and cleaning things up. My first problem came when I discovered that the blower fan was stuck on the motor shaft. I couldn't even get it to release with a gear puller. So out came the dremel with the cutting wheel.
That done, I could remove the motor and replace it with a new one (Napa part #655-1020 is a direct fit.) A quick browse through my parts bin found another fan to replace the one I cut off.
Even though the parts aren't visible, I finished my clean up, removed the little bit of surface rust with a wire brush and wheel, and then painted them up--should be good to go for another 60 years.