Well I know the 400hp was the 02+. so you must have gotten the 01 cam. I had that in my Z71 excab, it ran a 12.8 in the 1000', thats the only track we really have close to us so youd have to convert that to 1/4 mile time. You can shift it at 6k, power will top out at 5800. I made 266hp/263tq at the wheels with that cam.