Chevy Built One 850-HP Supercharged C8 Corvette Mule to Develop the ZR1

The 1,064-horsepower 2025 Corvette ZR1 has no equal. The last-generation ZR1 had a mere 755 horsepower—over 300 less than the C8 version. For that reason, developing this car presented some interesting challenges. How would the Corvette team develop the new ZR1’s tires, suspension, and powertrain without having any data on something that powerful? The solution was interesting, to say the least.

In a walkaround of a new ZR1 during the car’s reveal, the Executive Chief Engineer of the Corvette, Tadge Juechter, revealed how the company solved that problem.

“We had to cobble up a super high-horsepower, high-torque car,” Juechter said. “We built a mule. A hot-rodded [C8] Stingray, actually, with an LT5 in it. A hot-rodded LT5 with 850 horsepower and a sequential shift gearbox, to do tire development.”

While it sounds straightforward conceptually, Juechter had to sell upper management on the idea. “It didn’t take long for us to convince ourselves. Convincing leadership we need to go build this hot rod… oh we’ve gotta do this,” he said, recollecting the chat with company brass. 

The car did get built, of course, but it wasn’t exactly a sweetheart to run. “We put a smaller pulley on the supercharger and it used to just eat belts,” Chief Engineer Josh Holder said, laughing. It was all necessary to get anywhere close to the ZR1’s performance envelope, though. “In hindsight, it was too slow,” Chris Barber, the lead development engineer on the ZR1 noted. Despite this mule’s performance, it was still 214 hp shy of the production car.

“It seemed epic at the time,” recalled Juechter. But there was so much more to come.

Chevrolet Corvette C8 ZR1

It’s unclear what happened to this mule after the ZR1’s production-spec LT7 engine entered the picture, but judging by its track record for reliability, it was probably disposed of as quickly as possible.

Still, though, for a little while, this mishmash of odds and ends was the most powerful Corvette ever built by GM. If not a car worth keeping, it’s one worth at least remembering.