In 1980, a tiny French team's boss sat into the car he designed himself and pushed the pedal to the floor as long as he could so his co-driver could finish the 24 Hours Of Le Mans two laps ahead of Porsche's turbocharged 908/80 with Jacky Ickx and Reinhold Joest behind its wheel. Ickx (first) announced his retirement not long after the champagne wasting.
Jean Rondeau built his first car for the 1976 season. Powered by the 3.0-liter Cosworth V8 from F1 instead of the French PRV and badged as Inaltera thanks to the sponsor money coming from the producer of colored papers, the prototype finished 40 laps ahead of the next car in the Grand Touring Prototype category, a Lancia Stratos. They finished first in class and fourth overall the next year as well, before the team and the cars were sold off to Heini Mader. But Rondeau kept his drawings so he could build new cars.
The Rondeau M378 was ready by 1978, and used a steel tubular space frame with aluminium sheet reinforcement as the chassis. The Cosworth DFV V8 remained, and produced over 450 horsepower in endurance trim. Compared to the Inaltera design, the new Rondeau's fiberglass body had a longer tail and partly covered rear wheels. After struggling to find enough sponsor money, Rondeau had to wait two more years for the ultimate win.
In 1980, Porsche again sent no works Group 6 cars in order not to compete against their many customers in their 935 Group 5 cars. The only Group 6 Porsche sponsored by Martini Racing was entered by Reinhold Joest himself and Jacky Ickx. It was christened the Porsche 908/80 by the team, but looked much like the 1977 car. Outsiders believed it to be a hack on a 908 until it was discovered that it was in fact built on a real 936 replacement chassis, the 936-004. Porsche used a 908 chassis number as they didn't intend to sell 936s to customers.
Porsche's 2.1-liter turbo flat-6 had enough power, and Joest found himself in the lead. But when Ickx jumped in, the fuel injection pump belt gave up. Because racecar, Joest was prepared and there was a set of tools and a spare belt in the cabin, but the team lost 14 minutes and the lead. Ickx got it back at night, but instead of pushing even harder, they played it safe as they didn't expect the Cosworth to last long enough. But it did. When the Porsche got some gearbox problems, the French got ahead. For the final half an hour, it started to rain at Le Mans. The Germans were faster, but while Ickx pitted for wet tyres, Jaussaud kept the slicks. In the last lap, he lost control of the car, but didn't hit anything.
The Rondeau M378 won, with their second car being third overall and first in GPT. The Porsche 936 stuck between the French made Jacky Ickx so disappointed that he announced his retirement, only to change his mind four month later after Porsche promised him a unicorn.
Photo credit and hat tip to Ultimatecarpage!