S-Model?? How can i tell??

Ok- I picked up a M90 from a junkyard for $20. Yes, thats right $20. Felt no play in it, had it apart everything seems ok inside. Anyway how can i tell if it is te newer style S-Model? Are there any numbers to look for or distinguishing features that are noticeable from the outside? And one more thing, i read about superchargers having "play" in them. Is this refering to if you hold the pulley and pull it towards you and away from you and there is play or is it if you are holding the pulley and twisting clockwise and counterclockwise and get a bit of slip before the gears catch up. Thanks for any input you can give me. If it is a S-Model it is going on my 92SC tomorrow. And if the clockwise/counterclockwise "play" is the bad kind, time to replace the one on my ride.

Play is CW/CCW, and S-porting is porting done to a supercharger.

Someone correct me if I'm wrong.
Julian

I think you're wondering if it's the newer style blower right?
not the 89-92 style. If you look on the back side of the blower it will be angled, not squared like ours. I also think you need the plenum that goes to it. Or it won't fit. But not 100% sure.

If the inlet on the back is rectangular and not oval, its a newer style sc. You cant use it without a new plenum, the old style one wont work.

If it happens to be a new sc, you can look around for someone selling a new plenum (not likely), buy a MP one (www.magnumpowers.com, $500 but a very nice unit), or check out what Wynn has been cooking up: http://www.sccoa.com/forums/showthread.php?threadid=26213

-Travis
95 SC 5-speed

Thanks guys i'm gonna check on the blower tomorrow to see what it is but i'm pretty sure it is the older style. But at least I have a core now for a Magnum Powers upgrade. Or a backup if my original fails.