The Mazda 787 and its derivative 787B are Group C sports prototype racing cars that were developed by Japanese automobile manufacturer Mazda for use in the World Sportscar Championship, All Japan Sports Prototype Championship, and the 24 Hours of Le Mans from 1990 to 1991. Designed to combine a mixture of the Fédération Internationale du Sport Automobile (FISA) Group C regulations with the International Motor Sports Association (IMSA) GTP regulations, the 787s were the last Wankel rotary-powered racing cars to compete in the World and Japanese championships, using Mazda's R26B engine. Although the 787 and 787B lacked the single lap pace of World Championship competitors such as Mercedes-Benz, Jaguar, and Porsche, as well as Japanese Championship competitors Nissan and Toyota, the 787s had reliability that allowed them to contend for their respective championships. The reliability of the cars eventually paid off in 1991 when a 787B driven by Johnny Herbert, Volker Weidler, and Bertrand Gachot went on to victory in the 1991 24 Hours of Le Mans. As of 2021, this remains the only victory by a car not using a reciprocating engine design. It was the first victory by a Japanese manufacturer, and the only such victory until Toyota won the 2018 24 Hours of Le Mans. A total of two 787s were built in 1990, while three newer specification 787Bs were built in 1991. Development The initial design of the 787 was an evolution of the 767 and 767B designs that had been used by Mazda in 1988 and 1989. The 787 name was used instead of 777 to indicate a two-step improvement over the 767, and possibly over pronunciation difficulties of 777 in Japanese. Many mechanical elements of the 767 were carried over by Nigel Stroud when he designed the 787, but with some notable exceptions. Foremost was the replacement of the 767's 13J Wankel rotary engine. In its place, the brand new R26B was installed. The custom-built R26B featured a nearly identical layout and displacement, but included new design elements such as continuously variable intakes and three spark plugs per rotor instead of the 13J's two along with ceramic apex seals and variable length trumpets, among other modifications for increased efficiency. This allowed for a maximum power output of , which was reportedly limited to 700 hp during the 1991 race at Le Mans for longevity. The five-speed gearbox manufactured by Porsche, also mounted on the