Among collectors, the Porsche 917 is considered the most coveted race car the brand has ever built, and for two decades it has fetched top prices regardless of market conditions. The reason for this is obvious: The 917 represented the culmination of a development that began in 1966 with the 906 model and ushered in a new era of Porsche race cars. Although the 908, with its three-liter engine, won the World Championship in 1969, Porsche feared that its performance would not be sufficient to secure an overall victory at Le Mans—a goal that was just as significant for the manufacturer as triumphing over the Ford GT40, Lola T70, and the anticipated McLaren Group 4 Coupé. When the FIA lowered the production requirements for Group 4 five-liter sports cars from 50 to 25, Porsche saw its chance, and the 917 was born. Based on the 908 chassis, the 4.5-liter 12-cylinder 917 with an aluminum tubular frame was unveiled at the Geneva Motor Show in March 1969. On May 1, after 25 units had been built, the FIA homologated the 917 as a Group 4 sports car. Despite its tremendous performance, the 917 was not an immediate success. Its demanding handling deterred many factory drivers, who preferred to drive the more manageable 908. During practice sessions at Le Mans in 1969, drivers reported that the car became unstable on the straights at speeds exceeding 200 mph. Nevertheless, the 917 nearly won on its debut there—impressive proof of its extraordinary power and speed.
Nevertheless, the 917 secured its first victory in August 1969 in Zeltweg, Austria, with a short-tail coupé version. Over the winter, the John Wyer Racing Team (JW Racing) took over the operation of the 917 from the factory. Wyer had the rear section of the car redesigned—modeling it after the Lola T70 Coupé—which dramatically improved the car’s previously problematic handling characteristics. Under the leadership of Wyer’s Gulf Oil-sponsored team, the 917 won the Manufacturers’ World Championship in 1970 and 1971 before being banned again due to a rule change favoring three-liter prototypes. Porsche’s first overall victory at Le Mans came courtesy of a 917K fielded by the Porsche Salzburg team. In total, the 917 claimed 15 victories in 24 World Championship races during those two years—11 of them with the Gulf-Wyer cars. Considering this race car’s impressive track record, it is clear that the 917 ranks among the five most significant sports prototypes in history. No other two-seater race car has achieved more successes in the Manufacturers’ World Championship, the Can-Am Series, and the Interserie. Among its greatest triumphs are victories at the 24 Hours of Le Mans, the 24 Hours of Daytona, the 12 Hours of Sebring, and the 1,000-kilometer races at Monza, Spa, and the Nürburgring. No matter which racetrack you name—the 917 was there and dominated it.
As is so often the case, the decisive driving force behind the multimillion-dollar development of the 917 was the desire to win the legendary 24 Hours of Le Mans. But, typical of Porsche, the company didn’t stop at this goal: it also set its sights on the prestigious American Can-Am racing series. After all, at that time, roughly half of Porsche’s total production was destined for the United States—with further growth potential on the horizon. As early as 1969, Porsche had designed and tested the first open-top versions of the 917 specifically for the Can-Am series. This championship featured cars with enormous engine power that could only be mastered by drivers with exceptional stamina, determination, and driving skill. It was in this environment that the talented Swiss race car driver Jo Siffert entered the scene—a driver who possessed the ideal qualities to successfully pilot the 917 in this demanding racing series.
At that time, Jo Siffert was the most prominent driver on the Porsche factory team. Not only had he proven time and again that he was among the fastest drivers of his generation, but he also demonstrated remarkable loyalty to Porsche. Born in Fribourg, Switzerland, Siffert began his motorsports career on two wheels, achieving early success in motorcycle racing before entering Formula 1 as a privateer in 1962. He later raced for the Swiss team Scuderia Filipinetti and, starting in 1964, for Rob Walker Racing, where he claimed victories and gained international recognition for his composed driving style and his distinctive helmet featuring the Swiss cross. In 1969, Siffert competed as a semi-official Porsche driver in the North American Can-Am series, where he drove the open-wheel 917 PA (Porsche-Audi). The following year, he took on a special role: he appeared in the legendary Steve McQueen film *Le Mans*. The 1970 24 Hours of Le Mans also served as the setting for the film’s production—and the Porsche 917 in Gulf livery shown in the film, driven by the main character Michael Delaney, was actually driven by Jo Siffert and Brian Redman.Steve McQueen, who was a close friend of Siffert’s, drew heavily on Siffert for inspiration in portraying his film character Michael Delaney—right down to details such as the racing suit and wristwatch, which matched Siffert’s personal style.
Chassis 917/10-002
In 1971, Jo Siffert took it one step further: For the Can-Am season, he acquired a custom-built Porsche 917/10 Spyder with an aluminum chassis—a one-of-a-kind car with chassis number 917/10-002, which is now among the most sought-after examples. The car was completed in July 1971 and subsequently completed just 24 test laps on Porsche’s in-house Can-Am track in Weissach. It was equipped with a 4.5-liter engine and weighed just 733 kilograms. The very next day, the car was shipped by air freight to Watkins Glen in the U.S. There, the 917 was given a new identity—shaped by Siffert’s entrepreneurial spirit and creativity. As an experienced race car driver and shrewd businessman, Siffert secured a sponsorship deal with STP shortly before practice began at Watkins Glen. Overnight, the car was repainted from its original white to a striking fluorescent red and adorned with a large STP logo—a visually and marketing-wise striking appearance. Siffert’s team consisted of two talented Swiss race mechanics: Edy Wyss and Hugo Schibler. Both played a key role in the development and assembly of the car, which had been completed in less than four weeks at Plant 1 in Zuffenhausen. Together, they formed a well-coordinated unit that turned the Porsche 917/10 Spyder into an icon of the Can-Am era.
The race weekend at Watkins Glen took place from July 23 to 25, 1971, and featured a very interesting duel between the 917K and the 917/10. It is noteworthy that a six-hour FIA World Championship race was held that same weekend at Watkins Glen, in which Siffert also competed. His best lap time in the 917K was 1:08.510, compared to 1:08.640 in the 917/10. This clearly demonstrated that the barely developed, brand-new /10 was just as fast as the fully developed, factory-supported 917K. Perhaps most impressive, however, is the fact that Siffert finished second in the FIA race and achieved a very respectable third place in the first Can-Am race for chassis 10-002. After their debut at Watkins Glen, Jo Siffert, his team, and the 917/10 Spyder remained in the U.S. for the rest of the season to compete in additional rounds of the Can-Am series. During this time, the team achieved a series of notable results:
- Mid-Ohio – 2nd place
- Elkhart Lake – 2nd place
- Donnybrook – 5th place (after the car ran out of fuel)
- Edmonton – 4th place
- Laguna Seca – 5th place
At the end of the season, Jo Siffert finished fourth overall in the 917/10—an outstanding achievement, especially considering that he had competed in only six of ten possible races with the 917/10-002 chassis. Tragically, this success story came to an abrupt end: In October 1971, Jo Siffert was killed in a Formula 1 race. His death was a devastating loss not only for Porsche but also for the entire motorsports world, which lost one of the most talented and charismatic drivers of his time.
After Siffert’s death, the Porsche 917/10 was sold to Willi Kauhsen of Aachen. Kauhsen was a close confidant of Siffert’s and had close ties to the Porsche factory team, for which he worked as an independent test driver. Due to his extensive work with the 917 cars, he is likely considered the driver who has logged the most kilometers ever in a Porsche 917—a testament to his immense experience and technical understanding of this complex racing machine. Chassis 917/10-002 subsequently returned to the works racing department in Zuffenhausen, where it was extensively overhauled and prepared for competition in the European Interserie. This racing series was essentially the European counterpart to the Can-Am series and served as the successor platform for the high-performance sports prototypes after the regulations of the World Manufacturers’ Championship had changed. As part of this restructuring, numerous 917 models competed in the Interserie, which soon became a popular venue for the most spectacular and powerful race cars of their time. The 917/10-002 continued the model’s impressive success story there—now under the guidance of one of the most experienced Porsche drivers of all time.
With the 917/10-002 chassis, Willi Kauhsen achieved remarkable success and became a fixture in the Interserie. He engaged in thrilling duels with Leo Kinnunen, who competed in a factory-supported 917, as well as with numerous former Can-Am cars—including McLarens, BRMs, and Lolas—which were making their debut on European racetracks. After the first three races, Kauhsen had his car fitted with a turbocharged engine to outpace the growing competition in terms of power. The modification turned the 917/10-002 into a serious contender against the most powerful cars of the era. Kauhsen competed in nine races during the 1972 season, securing seven podium finishes and finishing the championship in second place overall—an extraordinary result and an impressive continuation of the legendary 917’s success story.
But the year ended tragically: In September 1972, Kauhsen suffered a tire blowout at the Nürburgring, which damaged the 917. Fortunately, Kauhsen himself escaped with only minor injuries. Despite the accident, he decided to keep the car. The damaged race car was eventually stored for 25 years in his brother’s possession—a silent testament to the eventful history of one of the most fascinating Porsche race cars of all time.
In 1998, the Porsche 917/10-002 underwent a comprehensive restoration. The car was completely rebuilt—by the same Porsche experts who had been involved in its original development at Porsche in the early 1970s. This authentic restoration ensured that every detail of the car corresponded to its condition at the time of delivery, both technically and visually. Upon completion of the work, the project was inspected and officially approved by Porsche itself. This is documented in a letter from Klaus Bischof—a longtime Porsche employee who, at that time, oversaw Chassis 002 on behalf of Willi Kauhsen. In the letter, Bischof, former director of the Porsche Rolling Museum, confirmed the authenticity and factory compliance of the restoration, which was carried out in accordance with the car’s condition in 1972.
For the reconstruction of the Porsche 917/10-002, the original Porsche design drawings and the original chassis components—which were directly owned by Porsche AG—were used. This allowed the reconstruction to be carried out with the highest precision and authenticity—fully in line with the original factory standards. The engine and transmission, both original components from the 917 era, were completely overhauled by the renowned 917 engine specialist Gustav Nietsche. Nietsche, who is considered one of the leading experts on the complex twelve-cylinder engines of these vehicles, ensured that the powertrain and technical components once again met the exact specifications of the original Can-Am race version. The body was built according to the 1971 Can-Am specifications and then painted in the distinctive STP red—the iconic color scheme that made Jo Siffert’s 917/10 world-famous during his American racing season. The result is a vehicle that represents an authentic resurrection of the legendary 917/10-002, not only technically but also visually. Upon completion of the extensive restoration, the fully reconstructed Porsche 917/10-002 was once again put to its intended use—driving. Willi Kauhsen himself presented the car at various demonstration and classic car events, including prestigious appearances at the Goodwood Festival of Speed and the AvD Oldtimer Grand Prix at the Nürburgring. These appearances impressively demonstrated that the 917/10 is not merely a museum piece but remains a fully functional race car of extraordinary fascination and performance.
The next chapter in the 917/10-002’s history took place in the U.S., where the car was displayed in a renowned private collection for over 8 years. In 2008, it was purchased by a German collector, who in turn kept the car until 2012. Another change of ownership followed in late 2012, and the 917 found a new home in an exceptional Porsche collection in Monaco. After acquiring the Porsche 917/10-002, the new owner had the car restored to its original delivery condition—the white paint scheme the vehicle bore when it was originally shipped to the United States. At the same time, the previously distinctive, angular body was replaced with a rounder body shape corresponding to the later stages of the 917’s development. In this configuration, the car was driven in 2015 by racing legends Jürgen Barth and Gérard Larrousse at the Dix Mille Tours on the Circuit Paul Ricard—a symbolic appearance that impressively underscored the historical significance of the 917/10. In 2017, the owner decided to restore the 917/10 to Jo Siffert’s legendary STP livery—that iconic fluorescent red inseparably linked to the Can-Am era and Siffert’s races. The body, which was still in existence, was also remounted on the car as part of this process. In addition, the vehicle was equipped with headlights to enable its participation in the Peter Auto CER (Classic Endurance Racing) series. This marked yet another chapter in the eventful history of this unique Porsche race car.
Over the past few years, the car and its owners have participated in numerous historic motorsport events, underscoring the virtually endless possibilities this racing legend offers its future owner.
- 2024 Spa Classic
- 2019 Techno Classica
- 2018 Spa Classic
- 2018 Espiritu de Montjuic
- 2015 Dix Mille Tours
- 2013 Dix Mille Tours
- 2009 Goodwood Festival of Speed
This Porsche 917/10 is now back on the market after being purchased by our company. A once-in-a-lifetime opportunity for any top-tier Porsche collection. Our sales staff is always happy to answer any questions you may have. Please note that vehicle viewings are generally only possible by prior appointment.
