Yeah, it should not be hard to turn. Should spin easily like it sounds like you suspected.
If the motor is out, are you talking about spinning by hand with the fan/squirrel cage still attached? Or are you just spinning the shaft?
If the shaft only, it would be a bit hard to turn. But once the leverage and weight of the squirrel cage is there, it should spin easily.
An old tired motor might actually turn on and spin, but they are usually not working to their best effectiveness.
As mentioned, the "Chevy" blower motor upgrade is a kick-ass upgrade, but even just a new stock heater motor is almost always going to get you more air flow (higher rpm) than an old tired one can give.
There is also a Ford truck motor from the full-size later model trucks that works well and does not require as much fiddling.
We sell the big one here:
http://www.wildhorses4x4.com/category/s?keyword=heater+motor along with the regular ones. And I'm very gratified to see that we finally carry a replacement resistor too! Finally!
The resistors don't usually wear out, but with all the restorations going on, and purchases of Broncos-in-a-Box these days, a lot of them come up MIA and in need of a new one.
Of course, you can always play with your old one and rebuild it with parts you can likely find online, or just by cleaning and lubing it. I'd go bigger though...
Lots of choices. Up to you then, but definitely do something about it.
Paul
