Designed specifically to win the Le Mans 24-hour race, the D-Type was produced by Jaguar Cars Ltd. between 1954 and 1957. Sharing the straight-6 XK engine and many mechanical components with its C-Type predecessor its structure however was radically different. Innovative monocoque construction and aerodynamic efficiency integrated aviation technology in a sports racing car, some examples including a renowned vertical stabilizer. Engine displacement began at 3.4 litres, and was enlarged to 3.8 L in 1957, and reduced to 3.0 L in 1958 when Le Mans rules limited engines for sports racing cars to that maximum. D-Types won Le Mans in 1955, 1956 and 1957. After Jaguar temporarily retired from racing as a factory team, the company offered the remaining unfinished D-Types as XKSS versions whose extra road-going equipment made them eligible for production sports car races in America. In 1957 25 of these cars were in various stages of completion when a factory fire destroyed nine of them. Total production is thought to have included 18 factory team D-Types, 53 customer cars and 16 XKSS versions. Because of the D-Types highly successful racing carreer, a number of replicas have been produced.