In the mid-1980s, Chevrolet aspired to create the world's fastest production road car, taking its C4-generation Corvette and turning to the UK-based Group Lotus for help. The result was the 1990 Chevrolet Corvette ZR-1 - an omnipotent road rocket powered by a 5.7-liter V8 with dual overhead camshafts instead of the typical cam-in-block design. It made 375-405 horsepower, depending on the year, which was enough to dispatch with the sprint to 60 mph in under 5 seconds and power on to a top speed of around 180 mph.

That was a lot of power for the time, but the production Corvette ZR-1 - the forebear to the several "ZR1" iterations that would follow - has nothing on this: a one-of-a-kind V12-powered C4 Corvette dubbed the "ZR-12".

The 1990 Corvette ZR-12, nicknamed "Conan" because of its brutally raw, beastly power, got its get-up-and-go from a twelve-cylinder Falconer racing engine, good for - wait for it - 686 hp and 680 lb-ft of torque. Those figures would be fit for a modern-day supercar, most of which can't touch the C4 ZR-1's low curb weight.

Granted, the ZR-12's weight was a bit greater than that of the production ZR-1; not only did the engine have 1.5 times the cylinder count, but Chevrolet also had to stretch the chassis by some 5 inches just to accommodate it. Total displacement, in case you were wondering, stood at roughly 600 cubic inches - about 9.8 liters.

So why did Chevrolet build a C4 Corvette with such an ungodly amount of power? The Dodge Viper. After GM caught wind that Chrysler had such a potent street weapon in the works, the Corvette team scrambled to find some way to ensure that GM's darling sports car wasn't beaten into submission. Ultimately, however, the business case just wasn't there; the ZR-12's Ryan Falconer Industries racing engine reportedly cost some $45,000 on its own, which is equivalent to about $89,000 in today's money, elevating the total price tag far beyond what most would consider paying for a Chevrolet.

It's a darn shame, too, because just listen to that V12 roar.