oddball

Battling demons with my '72 Cutlass A/C. Blower makes all kind of racket. Pulled it out, it's completely fine on its own. I have an OE wheel on it with an aftermarket motor. The wheel is pretty well balanced. Got another OE wheel, but that one wobbles like crazy.

I can't find any wheels other than the aftermarket with a set screw, which I personally hate.

Then there's this guy: http://www.thepartguy.com/acbox-cutlass.htm who talks about spacers. Any idea what he's talking about there? I took this thing apart the first time back in ..... 96? So there's certainly no spacer there now.

So, is this spacer actually a thing? Anyone have any? I haven't gotten a borescope up in there, but my guess is without the spacer, the fan is too far away from the firewall and just causes air to cavitate around the wheel?
Also looking for leads on wheels. Appears those guys have a line on useful plastic wheels. Sadly they aren't responding to my emails......