The birth of the 917 was both the technical subterfuge and calculated risk. Following the 1967 Le Mans 24 Hours and breathtaking performance of the Ford MK IV and Ferrari P4, the CSI (Commission Sportive Internationale, the forerunner of the current FIA) decided to limit engine displacement to three litres for prototypes. However, it also created a category for five litres with a minimum of 50 and 25 cars built. Porsche rushed into the breach and in the summer of 1968, and launched into the production of 25 cars of what would become the 917. This gamble could well have ruined the German marque, but instead it created one of the most fabulous racing cars ever made.

The 917 made its first appearance in the preliminary testing for the 24 Hours 1969. Two months later, it had a difficult debut at Le Mans. Despite the pole position Rolf Stommelen, both factory 917 retired, while the British gentleman-driver John Woolfe was killed at the wheel of his own in the first lap of racing. For 1970, Porsche entered into a partnership with the team of John Wyer, who won the 24 Hours in 1968 and 1969. After major changes, the 917 became the queen of endurance racing: in 1970, Richard Attwood and Hans Herrmann drove the car to the first victory in the La Sarthe for the Stuttgart manufacturer then Helmut Marko and Gijs van Lennep won in 1971 the following year.

Although Porsche also won twice with 917 K short tail, it was the long tail version (called LH) that entered into the Le Mans legend. Gerard Larrousse and Willy Kauhsen took second place in 1970, with the LH and its famous green and purple psychedelic decor. In preliminary tests in April 1971, a new extended version appeared, and set two records. April 18, Jackie Oliver lapped in 3'13''6 and was clocked at 386 km/h in Hunaudières (Mulsanne straight), at that time without chicanes. Forty years later, no one has ever gone faster on the 13 km circuit. Then in June, Pedro Rodriguez ran 3'13''9 to take the fastest pole position in the history of 24 Hours. The previous year, the long tail 917, Vic Elford crossed the threshold of 240 km/h average speed for the first time. In 1971, the 917 short tail of Marko and Van Lennep and even established a new record for distance (5335 km, 222 km/h on average). Faced with such an avalanche of performance, the CSI closed the loophole and defninatively limited the displacement of prototypes to three litres for 1972. This decision ruled-out the 917, that would find a new life in the CanAm championship in North America. It was not until 1976 that we would see another victory at Le Mans for a Porsche prototype... the 936.