The Z06 has a weight advantage, and more aggresive gearing, and a higher rev limit, and it's easier to drive. At the track, stock Z06's are fairly equal (it becomes a driver's race), modded Z06's will pull ground on me in the straights. Torque is a factor for the Viper though. Last year at an HPDE, I had a highly modded Z06 behind me. (13 grand of power-adder upgrades to the motor/and racing brakes) He would be on me pretty good the whole course but couldn't get around me because of a long uphill sweeper, the Viper would gain enough space to not be in the way or hold him up. I talked to him after the session, and he said that Vipers always seem to do that there with the crazy torque up the hill. .....In a street race, or highway pull, the Z06 would probably win though.