The Chevy Corvette is remembered fondly as the most American of American sports cars, but in the 1950’s it had plenty of competition. While its best-known sales adversary was the Ford Thunderbird, there were even better cars for those who wanted an open-roof roadster with lots of performance. Those in the know opted for the Kurtis 500KK, a Chevy-powered droptop that put both the Corvette and Thunderbird to shame.

Alas, few of these rare cars were built, and even fewer survive today. One of these automotive unicorns has shown up at the Hemmings Auto Blog with an asking price of $695,000. That’s more than most Corvettes and Thunderbirds will ever be worth.

What you won’t find here is a Chevy small-block V8. Rather, the Kurtis 500KK made due with a supercharged 235 cubic-inch inline-six cylinder engine from Chevy with twin Zenith sidedraft carburetors (though we should note that these cars were typically fitted with twin Strombergs). Sold as a kit car, the Kurtis KK came with an all-aluminum body and a tubular frame chassis, keeping weight (and weight balance) in check.

Powered by a supercharged Chevy I6, the Kurtis 500K was a light and nimble

This well-documented original dates its history back to the fall of 1955, and while it has a Chevy engine, the 3-speed transmission, brakes, and rear end all come from Ford. The asking price of $695,000 is crazy-high, but very few of these cars were built (estimates place the number between 30 and 40 units). Furthermore, their contribution to American motorsports can not be understated. A

t one time Kurtis was the go-to-builder for American road racers. Now he is just another mostly-forgotten name on a high-priced classic.