I think that's a great time. I don't expect that GM is holding back. That's clearly the best time that they've run or they wouldn't have posted it. It's an awesome time. Anybody thinking sub 7:30's was kidding themselves. The ZL1 is better suited for a track of this size. After seeing that lap, I'm quite frankly amazed that the ZL1 went 7:41. Both of these ring times are amazing for muscle cars.
I'd expect bigger gaps between the two Z's on smaller/tighter tracks. I say well done GM. That's an incredible lap for a big heavy Camaro.