The C6-R is a racecar built in 1955 to be driven by American sportsman Briggs Cunningham at that year's 24 Hours of Le Mans race. It was preceded by the C-5R, and was the last automobile manufactured by the Cunningham Company.
The vehicle was fitted with a four-cylinder Offenhauser 3-litre engine capable of generating 260 bhp at 6000 rpm. Its aluminum body was low and smooth, and weighed only 1900 lb, making it much lighter than many of its predecessors. Ordinary front suspension was employed, while a de Dion system was used for the rear.
The car's transmission was broken during its first race at Sebring. At the subsequent 24 Hours of Le Mans race in 1955 the vehicle's second and third gears failed, and its engine, which was designed for methanol fuel and insufficiently modified for the mandatory French pump gasoline, overheated. With the C6-R being incapable of running with a burnt exhaust valve, Cunningham was forced to retire the race.