SN92 help

Ok, I have finally got the Paxton on the 86' Mustang and checked everything out, everything seems functional. I now have the boost guage connected at the vaccum tree and went to get a reading to see what I'm pulling. I thought I would have gotten a decent amount of boost around 6. I seem to get getting around 2-3 lbs of boost and that is only at WOT. I went to check the belt and seem to be showing signs of slippage so I tighen it down a little be more and checked again. This time I got an average of 4.5. and a little sqeeling noise at the higher RPM, seems to be coming from the blower. and the belt jumped a little off the blower pulley.

I'm now a little lost for words. I'm new to the supercharging game here, so bare with me on this.

What would have caused the belt to jump like that now?
Also I noticed that the reading on my gauge at Idle is reading about 15- 20 on the vaccum side is this normal?
Now one thing I have noticed is when I hit WOT and get a boost reading I'll get around 3-5 and then it will start to fade downward before shifting, is this normal?
Also how much boost should I be seeing with the setup of the stock paxton blower pulley, which I believe is 4.25. and one piece crank with the 7" and 4" crank pullies?

Overall I definately feel the power on the streets, no problem with that. I just sort of figured I would have a more stable reading without having it at WOT all the time just to get a boost reading.

Ben

5psi would be correct at WOT
You need to check alignment of your blower-crank-tension pulley. The problem could even be flex of your bracket and at WOT your belt is jumping because of the belt vibrating because it is not keeping a constant tension.
When the belt is off the supercharger how much in and out movement do you have on the front blower pulley bearing?
Your vacuum reading is normal between 15-20 hg.

Think I solved the belt issue. Apparently I didn't have one of the tensioner bolts not tighten down all the way. After adjusting that. I seem to be getting 5-6 lbs of boost.

I checked the blower pulley It seems to be pretty tight. very little to none as far as movement goes.