That idler does look crooked on the picture. Or maybe it is just the way the picture was taken. You should take a steel rule and lay it'* edge on the sc pulley rim, and see if the idler is parallel to it.

That'* a good idea......but you should be able to see a wobble at idle. If that isn't the case, I'd say the shoulder on your input shaft of the SC or the pulley is wrong. One or the other.

Anybody got a 92/93 supercharger laying around that can pull the pulley and make some measurments?

Are you sure you put it on 'frontwards' ???

Yes, I did. If memory serves, the hole in the pulley was right. Just about right at 5/8". Which leaves about the only other possibility, something is wrong with the shaft. Does the shaft turn down to accept the pulley? Is there supposed to be a stop on the shaft?

I had to thread the nut to push the pulley on. Perhaps I cranked it too far initially?

Guess I'll have to pull the 2.2":

Another thought just hit me. We know your stocker was ok. So something changed during the swap. Either the 2.2" pulley is wrong, or something else.

Question......are you sure the key was installed correctly when you put the pulley on? That could explain alot. The pulley would slip, gall the aluminum 2.2", and allow it to wear and walk towards the ND.

Well, it didn't "walk" toward it. It was almost touching when I put it on the first time, and threw the belt 3 minutes later.

You're going to have to pull that sucker, bud. And you still have your stock pulley, right? For comparison? Just remember that the PB pulley is aluminum, so you have to be more careful with the puller on it than the stock steel pulley.

I mentioned this to Brian, having to use a puller, and he replied:

Mine went on tight. It may be machined for a slip fit, but the anodizing adds material to the inside face that mates with the shaft? Just a theory. Mine went on HARD, even after cleaning the input shaft with 0000 steel wool and WD-40. I made my own custom puller to do the job, modelled after Brians S2 puller, but smaller to fit my 2.5-2.2'*.

Mine did, too. There'* no way I'd get it off without a puller, personally.