Cursory Inspection, and Pulley Measurement question

Hey, Quick question. I received a SN 2000 today, during my cursory inspection (at work on my desk) I noticed that if the blower is sitting inlet side down and I tug on the pulley it moves about 1/16” up before the supercharger lifts off the desk. Is the pulley normally a little loose in-and-out, or should it be dead tight?
I may just pull this apart and inspect before I use it anyway. No ratcheting when turning the pulley, smooth but does take effort.
Second question, are the pulleys measured by the diameter or by the circumference divided by pie? Across the face of the pulley it measures 4.5”, but by measuring the circumference it measures out to 4.30”.
Thanks.

1/16" is correct on the in and out movement. Across the face is the usual measurement by most but I always use the circumference because I would have the sides of the pulley milled higher to keep the belt from jumping off the sides.

Thanks for the reply. Cool then with a 7" crank pulley and the 4.5" charger pulley that will put me <42k @ 6000rpm. Hopefully that will generate around 4psi. I'm looking forward to playing with this Supercharger.