Start the car but do not rev up the engine . . . Is the thick black ring behind the supercharger pulley backing plate turning? Use a small rubber mallet to put pressure on the black ring and see if you can easily stop it from turning. If you can stop it, your supercharger is not engaged but just free wheeling spinning. You're OK . . . that won't hurt anything. The fact is that the supercharger engages when you first rev the engine over about 1500 RPM and then it stays engaged until you shut off your engine.

If you can't easily stop the black ring from spinning when you first started the car, then you should remove the pulley and put a thicker (or a second) shim ring behind the supercharger pulley (just to be sure the supercharger pulley will hook up properly when it is engaged).