Only one exists.

At the 1989 Detroit Auto Show, Dodge revealed the Viper and its V10 engine, and General Motors believed it’d be a formidable competitor to the Chevy Corvette. In response, the automaker commissioned a chassis study in the early 1990s to see if the Corvette could accommodate a V12 engine. Why not outdo Dodge with two more cylinders, right? Only one example was ever built, and the idea never passed this stage of development.

The DtRockstar1 YouTube channel recently got the opportunity to capture the V12 Corvette on camera, including the V12’s burbling exhaust note. Chevy called it the Corvette ZR-12 and sourced the mill from Ryan Falconer Industries. At the time, the 600-cubic-inch – 9.8-liter – V12 found use in marine vehicles, but it served GM’s need perfectly. However, the project involved more than slipping a bigger engine under the hood. The chassis needed an additional eight inches added between the passenger compartment and wheels to accommodate the larger vehicle.

In total, the chassis extension and the larger V12, which replaced the Corvette’s V8, only added 100 pounds (45 kilograms) to the car’s curb weight. That’s nothing the V12 couldn’t overcome, producing 686 horsepower (511 kilowatts) and 680 pound-feet (921 Newton-meters) of torque. In March of 1993, Motor Trend tested it, recording a quarter-mile time of 11.6 seconds at 133 miles per hour (214 kilometers per hour). Dodge claimed the 1993 Viper could run the quarter-mile in 12.9 seconds at 113 mph (181 kph).

So, why did Chevy abandon the project then? Cost. According to the National Corvette Museum video above, each V12 engine had a $45,000 price tag. That’s a difficult price to swallow today, let alone in 1993. The only example is at the museum, on loan from GM. Initially, the ZR-12 had different wheels and side-exit exhaust, but those have been lost to time. Imagine how different today’s C8 Corvette would be if GM ok’d the V12 in 1993, and it stuck around.