Notice anything odd about the photo above? Before the existence of the Daytona International Speedway, the Florida race occurred in part on the sand next to the Atlantic Ocean. Plus, every other NASCAR you have ever seen was likely a hardtop. However from 1956 to 1959, there was a series for convertibles. 

Like with the Superbird, this was an era when there was a real connection between the race cars and the street models. The photo above shows driver Curtis Turner in the 1956 event's race-winning #26 Ford Sunliner. Joe Weatherly is in the #12 Sunliner behind him.