the cam works from 2500 to 6500 and its at about 6800 it sounds like a sputter..i looked at the plugs yest. and the fr. plugs dont look as good as the bk.....the # 1 and the # 2 look a little diff. than the rest but the bk 5/7/6/8 looks great...3/4 looks better than 1 and 2.....also my dist. is locked out timing is set at 33 plan to change it when i go back to the track tomm. i hope..