Today, the two men routinely test cars at GM’s Milford proving grounds, sharing feedback with top engineers like Corvette’s Tadge Juechter and Camaro’s Al Oppenheiser. GM CEO Mary Barra also visits Milford’s proving grounds, though usually on her own schedule. Last October, Ammann and Reuss took the ZL1 to Nurburgring where the car lapped while wearing leopard-spotted camouflage. They liked the result.

“The best Camaro I have ever driven,” says Reuss.

Ammann says, “It cuts like a knife. It makes 640 horsepower feel more approachable.”

The product of more than 100 hours in the wind tunnel, the muscular Camaro is 200 pounds lighter than the previous-generation ZL1, gains 60 horsepower and features 11 heat exchangers to cool the 378-cubic-inch monster beneath its aerodynamic skin. But the ZL1 is more than a fast muscle car.

It is also the first application of Chevy’s high-tech, lightning-quick 10-speed transmission. Jointly developed with Ford and planned for eight Chevy models for model-year 2018, the 10-speed shifts faster than many dual-clutch transmissions found in supercars.

The ZL1 also gets six-pot Brembo brakes with 15.35-inch rotors the size of Captain America’s shield; Recaro seats; wider front fenders; and special Goodyear tires.

It goes on sale this fall.

“The Camaro ZL1 is designed to excel at everything,” said Reuss. “Acceleration, handling and braking — with the highest levels of technology and perfect chassis damping, (it’s) suitable for everyday driving. It will compare well to any sports coupe, at any price and in any setting.”

At Spring Mountain, Reuss piloted a 10-speed, Ammann a 6-speed manual.

Who’s faster on track? “That’s classified,” jokes Ammann, his hair matted after 22 hot laps.

“Honestly, we don’t (compare lap times),” says Reuss. “We never do that because when you get into that sort of thing it’s not safe.”

Camaro sales are up 44 percent this year over last, the Corvette Z06 is clocking test times quicker than $200,000 Lamborghinis, and the development teams are having fun.

“It beats the office at the Ren Cen,” Ammann says.