The fifth and the last of the 718/2 F2 cars, with chassis number 718/2-05 was an experimental formula racing car. It had the 718/2 chassis, but a different body. The car never got its own type number. It was a one-off car, continuous development project that later evolved into something that became the prototype for the 1961 Porsche 787 F1 car and then even for the 1962 Porsche 804 F1 car. 718/2-05, was first seen at the F2 race on Solitude race track near Stuttgart in July 1960.
In 1959 Porsche unveiled the prototype of a narrow, open-wheeled car called the Porsche 718/2 that married the 718's mechanicals with a more traditional single-seat Formula body. For 1960 the production 718/2, starting with chassis number 718201, received revised bodywork, a 6-speed transaxle, and a wheelbase extended by 100 mm. A total of five cars were built. Some of these four-cylinder cars were later raced in F1 under the 1962 1½ litre formula.