I bought a 2008 GT500 with the KB 2.8H stage 3 kit already installed. I currently have the 3" pulley and the p1 program installed. I have stock exhaust and drag radials. Here is the problem. When i had it dynoed it made 610 rwhp on a Dyno jet and last night it ran 122mph in the quarter. Both numbers seem low to me. The old owner said it made 680 rwhp. I currently have 3300 miles on the car. Do you think something is off on the Hp numbers and trap speed? Kenne Bell says it should be making close to 700 rwhp. I also posted this in the KB tech area and didn't get any replys. Thanks Tim