I'm on the stock belt with a 15% alt a pulley and I'm no longer getting full boost on my gauge. My best is old,85k miles, and stock size. Could I be loosing boost there? Thanks

 

If your running the stock belt you need to replace it. Also make sure the tensioner is in good shape and the bushings on the tensioner shock are in good shape. If you need either let us know.

 

Would an old and worn belt be causing me to loose a couple of pounds of boost?

 

Stock belt is 1388mm. I have a 1374mm belt to get the proper tension. Inner tension rod should have one hole showing (about 8-10mm shaft length). Worn out belts can get a "glazing" effect on them, which can cause slippage. Replacing the belt is a good place to start.