[BNaylor]

How does power feel since the supercharger was replaced? I'm assuming you are using the stock 3.8" SC pulley. As long as you are sure the job was done right and the boost valve is OK maybe it is just a problem with the boost indicator. The stock one is not that accurate and not indicative of real boost. For that you'll need an aftermarket boost gauge like an Autometer. The aftermarket gauge is more accurate because it will obtain the boost reading off of engine vacuum and ties into the MAP sensor vacuum lines.

Another suggestion is to hook up an automotive vacuum gauge and see if engine vacuum is in specs.