Chevrolet released this video touting how they have to turn down the power in their car to go racing in ALMS against Porsche, BMW, and Ferrari. Yes, the ZR-1 is a powerful car but what is with the cheap shot Chevy? Your ALMS motor is based on the Z06, not the ZR-1. Secondly, didn't BMW beat you last year with less displacement and start off this year winning Sebring in 1st and 2nd? Maybe you need the extra power.
Details on the ALMS motor, 5.5 liter based on the LS7, not LS9: