How new is your motor? I run a stock black ae pipe, and a p4 plug, After about 2 gallons, the motor runs great, always comes off the track between 240 and 250 running as good as it will get. The motor is tempermental until the 1 gallon point,( I have broke in 2 of these motors at the same time, same result with both) after the 1 gallon mark, it becomes very easy to tune, and idles great. Did you put the shim in that came with the motor, and remove the stock ones after break in? I get between 9 and 10 minutes on a hardpacked clay track, 90-100 degrees outside by the water in buggy, and 10-11 in truggy. Have you tried gearing up the car? Try a 16t clutch bell. These motors have very little top end at first, but the car comes alive after time.