From the moment it hit dealership lots in April of 1964, the Ford Mustang was a huge hit with a wide variety of car buyers, from secretaries to race car drivers. The aftermarket responded immediately with go-fast parts and custom exterior options. For those wanting something really different though, there was the hardtop convertible designed by Ford engineer Ben Smith.

Very few people opted for this kit, making it a rare find, but Hemmings Auto Blog came across just such a car for sale in their classified section. Sure it’s a six-banger, but it’s still pretty cool if you ask us.

Cool, and rare, as there were just 14 of these hardtop convertible Mustangs ever made. Smith was the man responsible for the retractable hardtop on the 1957-59 Ford Fairlane 500 Skyliner. He developed one test Mustang for Ford, which passed on the option, allowing him to sell his own kits converting coupes into convertibles.

Sure, it would have been easier to just buy a convertible, but the kit also gives the Mustang a very unique look, along with a cool feature that you just don’t see very often. Alas, hardtop convertibles have been a hard sale for some brands, as the additional cost and lack of trunk space can be a deal breaker. In this case, the Mustang also lost the back seats as well.

Despite being a six-cylinder though, this Mustang is cool in its own, unique way, and the $21,000 asking price isn’t entirely unreasonable, considering many well restored cars go for that on their own, let alone with such a unique aftermarket option. Tell us what you think of the hardtop convertible