GM’s Blackjack Test Mule Helped Keep C8 Development A Mystery

After half a decade of secrecy, GM finally introduced us to “Blackjack,” the Holden test mule used during C8 development.

Months before the C8 finally made its debut, General Motors had C8 test mules that would occasionally pop into the public eye here and there. They would end up being very close to the production car we know of now. But it was 5 years ago when we first hopped on the mid-engine Corvette bandwagon via spy shots. That hype was due to this car, dubbed “Blackjack,” which Corvette Forum recently saw in person during the 2020 C8 Media Drive.

MotorTrend gives GM employees credit for naming the car. With the front of a Holden, the center cab of a C7 Corvette, and wooden rear bumper, “Blackjack” can never be called pretty. But beauty wasn’t its purpose. Important initial testing performed by the Blackjack test mule helped develop future mules. Very interesting details are part of the test mule. For instance, Hagerty reports those wing mounts are odd-looking for a reason.

They are wooden, for one, but also hollow in order to direct cooling to the engine and transmission. After all, the engine cover is solid with no venting at all. Vents would have given spy photographers a crystal-clear indication of where the engine is located. WhichCar, a publication out of Australia, reports the wing was slightly inverted to create aero balance, rather than downforce.

A Porsche PDK gearbox accepted power from the C7 small block engine. This PDK gearbox served as a benchmark for GM’s development of its own unit. WhichCar then spoke with Corvette chief engineer Tadge Juechter about the PDK and the Chevrolet dual-clutch. Juechter told them development “took as long as designing the rest of the car.” Under the car, Hagerty says the car was on coil springs all around.

Of course, as all of this was being developed, GM needed (or preferred to) keep it a secret. Some of the first spy shots of Blackjack were snapped in 2015. Car and Driver was one of the first to publish images of the new mid-engine beast, but also to see how the car would be hidden as soon as they felt it was being spied. Car and Driver also noted that GM employees would often cover Blackjack with a car cover. Sometimes with its test drivers still inside the car.

The fact that Blackjack even exists today shows GM has no intention of destroying such a significant development vehicle. Sure, it might be an ugly Frankenstein of parts, but its history in the Corvette lineage is almost as important as the first one off the line in 1953.

Photos by Derin Richardson for Corvette Forum

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