I have been installing the sport 500 turbos since 1990 and I have never seen a set dyno that low at that boost level. I think you are looking at the wrong area to make changes for improvement. Based on your dyno results compared to what is normal, I would say you MUST have other problems. We have a sport 500 automatic car that makes 487 RWHP. The average is 450 to 500 RWHP at that boost level. The two areas I would look at if it were me would be.... 1. Cam Timing 2. Torque Converter problems or trans problems. Cam timing is huge for how a engine with turbos moves air. The converter can rob tons of power if not designed properly or if something move internally in the converter. The transmission could also have a bind if everything is not perfect. I have seen poor auto trans rebuilds rob over 100 HP. When upgrading valve bodies you really have to do a ton of testing to get it right. Best of luck
