After a major internal power struggle, engineer Ferdinand Piëch, the grandson of Ferdinand, took control of the marque's racing programme. He nixed the Porsche 904 conceived by his cousin and now rival, Butzi Porsche (the father of the 911), to launch a programme aimed at winning the 24 Hours. The effort began with the 906 and carried on with the 907 then 908. Each car's design followed Piëch's credos: tubular chassis, clean aerodynamics favouring top speed, a flat and air-cooled 6 then 8-cylinder and 2 then 3-litre engine.

At the end of 1967, the CSI (Commission Sportive Internationale, predecessor to the current FIA) announced the ineligibility of prototypes exceeding 3 litres. The 908 (8 cylinders, 3 litres) was built in a long version for fast tracks and in a spider version (908/2) for slower tracks. However, the car was not destined to become the first Porsche to win Le Mans: due to a lack of reliability in 1968, and for coming up short by 120 meters in an unforgettable final against Jacky Ickx's Ford GT40 in 1969.

To keep starting grids stocked, the CSI created in late 1967 a Sport class for cars up to 5,000 cm3, with a minimum production quantity of 50 cars. This made way for many Ford GT40s and Lola T70s to continue racing, with Ford winning in 1968 and 1969 thanks to the Wyer's Gulf team.

1969 | Ferdinand Piëch's wager

Piëch decided to go all in after the CSI reduced the minimum number of cars to 25, focusing his full attention on the powerful 917 presented at the 1969 Geneva International Motor Show. All 25 cars were lined up in the factory courtyard for the CSI inspection on 31 March 1969.

The 917's tubular chassis was a widened and reinforced version of the 908's with an initial innovation of welding the tubes together and introducing pressure. A gauge then made it possible to ascertain whether the pressure was still present each time the bonnet was opened. A weld failure or a crack would have caused the pressure to drop in the chassis and signal there was an urgent repair to be made.

The aerodynamics also derived from the 908, either with the long tail dear to Piëch, or with a more manageable slightly truncated version. In both cases, the car was equipped with a rear stabiliser connected to the suspension, reinforcing the support on the rear axle.

Porsche drew on its experience to create its first 12-cylinder (580 hp) engine for the occasion. Starting from two air-cooled flat 6-cylinder blocks, Porsche "assembled" them with a single crankshaft, but with distribution driving the camshafts located in the engine centre between the two banks of 6 cylinders, as well as an additional shaft driving the cooling turbine, igniter and alternator. The drive of the gearbox was done by a flywheel located at the rear.

Finalised, the 917 was entered in the preliminary tests for the 24 Hours of Le Mans. A beast in acceleration yet very tricky to drive, it clocked the fastest time. But drivers weren't scrambling for their chance behind the wheel. Additionally, during the official tests in June, the CSI decided to prohibit mobile fins. Porsche's drivers demonstrated the 917 was undriveable with fixed fins. The CSI granted permission, but not for the other prototypes (908, Matra).

Having clocked the quickest times during the pre-race sessions (between 03:22 and 03:27), the three official 917s were gaining 10 seconds per lap on the 3-litre prototypes and Ford GT40s. Unfortunately, the reliability just wasn't there yet: one failed to start, one experienced an oil leak during the 15th hour and the third lost its clutch after 22 hours. Tragically, the private 917 fielded by British driver John Woolfe had an accident in the first lap, resulting in his untimely death.

1970-1971 | Two wins despite internal strife

Porsche was fully determined to win in 1970. Rather than battle Wyer's team who had already defeated the marque twice at Le Mans, the decision was made to entrust him with the cars (Gulf Porsche). At the same time, to increase its chances, a team in the name of Louise Piëch, Ferdinand's mother, was formed in Austria (Porsche Konstruktionen Salzburg, which would become Martini Porsche in 1971).

The first testing sessions with Wyer's team were held in Zeltweg in September 1969. The drivers still complained about the 917's grip level. Wyer's technical director, John Horsman, noticed the gnats splattering the front of the car were not dirtying the rear wing, thus detecting an aerodynamic anomaly. With the help of a few aluminum sheets, he redesigned the rear bonnet. This was to become the third innovation of the 917 K (for Kurtz meaning short). The final bonnet largely cleared the rear wheels and offered a wedge profile that would become standard on Sport and Prototype cars (Ferrari 512 then 312, Matra, Alfa Romeo, Porsche 908/3, etc.) in 1970 and 1971.

This major change inspired Ferdinand Piëch who believed more than ever in his long tail design. He had a specific long rear bonnet created (the fourth innovation) for the 1970 24 Hours. The top speed was phenomenal in the Mulsanne Straight, yet the lap times were very similar between the long and short tail. Wyer stayed with the short version, and only the Austrian team opted for the long. Of the two long tails fielded in the 1970 24 Hours, only the pop art livery car of Gérard Larrousse/Willi Khausen finished the race, second behind the short tail of Hans Herrmann/Richard Atwood. Interestingly, Wyer's Gulf cars benefitted from a new displacement of 4,900 cm3 making it possible to attain more than 600 hp. However, for once, Wyer had made an error in judgement: none of his three cars reached the chequered flag. The Salzburg team's two 917s that had achieved the one-two were equipped with 4.5-litre engines.

For the 1971 running of the race, Porsche worked with the French company SERA to improve the long 917. Retooled at the front bonnet to lower it significantly and at the rear bonnet with semi-faired wheels, the car became the queen of Mulsanne. The drivers were impressed with both the speed and stability of the car, and Wyer opted for two. Clocked at more than 394 kph during testing and at 388 kph in-race, it would take 17 years to see the WM beat the record at more than 400 kph. 

The 917 K also evolved, with two large longitudinal fins on the rear bonnet. It was this version, led by Helmut Marko (now Red Bull's F1 adviser) and Gijs van Lennep, that claimed the top step on the 24 Hours podium and proved once again a long tail is not essential at Le Mans.

The CSI once again limited sports cars in 1972 to 3-litre engines for endurance racing. But Porsche had already anticipated the change the previous year and fielded a 917/20, an enlarged version of the 917, foreshadowing a 917/30 Can-Am version with a twin-turbo engine that would dominate the series across the Atlantic after 1972. The Le Mans model's livery made it even more unique: as a wink to the sheer size of the car, Porsche's team painted it pink and outlined the various cuts of pork, hence its nickname the Pink Pig...

PHOTOS (Copyright - ACO Archives): LE MANS (SARTHE, FRANCE), CIRCUIT DES 24 HEURES, 24 HOURS OF LE MANS. From top to bottom: the 917's various aerodynamic evolutions: the 1970 long body in psychedelic colours (#3) pole-sitter that year; the 1969 version with mobile fins at the end of the rear spoiler (#12); the version entered by John Wyer's Gulf team that featured a rear defined by engineer John Horsman, as well as a small spoiler placed at the rear centre; recognisable by its streamlined rear wheels (with a slit as an air intake), the 1971 long version (#17) that established both an absolute circuit record and a speed record in the Mulsanne Straight; the famous 917/20 version called the Pink Pig in 1971 (#23) prefigured the 917/10 and 917/30 versions that competed in the Can-Am Challenge Cup in North America in 1972 and 1973.