Thanks to Butta on CorvetteForum for posting this info and GDP for posting the text with the important part hilighted:
GM Performance Division will unveil two new concept vehicles for the Woodward Dream Cruise next week: a modified Pontiac GTO and Chevy Colorado pickup. The modified GTO and Colorado are "Employee Enthusiasm" vehicles, an internal volunteer program that gives younger GM engineers the opportunity to manage a concept car from start to finish. The first public showing for the vehicles will be at a Woodward Dream Cruise press conference Tuesday, Aug. 17 at Pioneer Park in Royal Oak. They will then be on display at Athens Coney Island throughout the Cruise.
The GTO concept has a 6.3 L V8 engine with 500 hp at 5200 rpm and 500 lb-ft of torque at 5000 rpm, matching early rumors about the LS7 for the C6 Corvette Z06.
It also has a six-speed manual transmission, modified brakes, bigger wheels and tires and new exhaust. The bright orange exterior features a new hood, fender, quarter panel, spoiler, front and rear fascia and rockers.
The Chevy Colorado concept has a 6.2 L engine that makes 420 hp at 5600 rpm and 420 lb-ft of torque at 4600 rpm, sure to fuel speculation about a V8-engined Colorado. The wheels and tires, brakes, suspension and exhaust systems have been modified, and the exterior has new front fascias, front and rear wheel flares, hood, modified rockers and custom side mirrors.