Hello everyone new to the forum. About a year ago I purchased a 2003 grand prix gtp that already had a 3.4 pulley, zzp xps cam shaft, upgraded rockets, zzp headers, cold air intake, and no cat but stock muffler. The thing that I'm curious of is it has a boost gauge but it is only reading about 5.5lbs max. From all the things that I have read on these cars is that it should be making more than that. Not sure if maybe the gauge was possibly installed wrong but was curious if any of you had an idea on why it is reading so low.