Take them both to the track. The power of the LS1 is very deceiving with the flat torque curve. I had a 98 Z28 and an 01 SS. Both cars would hand
my C its butt. BUT!
the C can carry my family in comfort on long trips where the Camaros could not. And the C has more/better creature comforts.
Is your Z an A4 with 2.73's? That could explain the feeling your getting as well. Both of my Camaros were M6/3.42 cars.