That's interesting. That new Z06 /Z07 is not performing to where it should be. It's less than 3 seconds a lap faster on the same track with the same driver as the Z/28 (1:27.10 Z06 vs 1:29.72 Z/28).
Also, looking through it's straight line speed I can tell you positively, that car likely does not have 650 hp at the crank or GM has retarded aero that does not work. Randy Pobst mentions that in the article, "It felt faster [than the lap time], but it also didn't feel like it had 650 horsepower," Randy said. "Just not as fast as I expected."
Seeing as how under-performing the new Z06 has been from an engine standpoint, my guess is that this car either suffered horribly from heat soak or something in the factory tune caused the engine to make about 100 hp less than it should have.
Either way, both cars are seriously fast but I imagine with a healthy Z06/Z07, that the GT-R would likely have lost by 1-1.5 seconds.
99 Chevrolet Camaro Z28 M6 - 6.676 @ 103 in 1/8, 10.512 @ 130.2 on street tires, H/C/I
93 Eagle Talon TSI AWD 5spd - Built 6 Bolt, 16G Evo3, HKS 272 Cams - under construction
94 Mustang GT - 5.0 bored and stroked to 347, Vortech V1 @ 10 PSI, Tremec TKO 600 - PIA