When it competes in the IMSA WeatherTech SportsCar Championship, Porsche’s 963 race cars will compete under two historic numbers: 6 and 7.

These lucky numbers come from Porsche’s last partnership with Penske, with which it collaborated from 2006 to 2008 in the American Le Mans Series. At the time, the numbers 6 and 7 graced its yellow prototypes, the Team Penske Porsche RS Spyder, and the numbers saw the cars to great success.

“When I see our new Porsche 963 decked out with the race numbers 6 and 7, it evokes wonderful memories of the glory days with the RS Spyder in the USA,” said Thomas Laudenbach, the VP of Porsche Motorsport. “We won everything there was to win back then. For us, it was about class victories in the LMP2 category, but we still managed a major coup: Overall victory at the 12 Hours of Sebring. We’re now eager to add to these great and triumphant times and fight for overall victory at Daytona, Sebring and other events in the IMSA WeatherTech SportsCar Championship.”

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The number 6 car was the first to earn success in the ALMS series. At the end of 2005, Lucas Luhr and Sascha Maassen earned the Porsche RS Spyder’s first class victory at its final test outing at Laguna Seca. The number 7 car wasn’t far behind, though, and it earned a total of 16 LMP2 victories over its three years of competition.

“Thanks to these wins, the number seven has turned into one of my favorite and luckiest numbers,” said Timo Bernhard, who won two championship titles during that era.

The history of the numbers actually stretches back farther than that, though. As Roger Penske, the owner of Team Penske, notes, a number of Porsche Penske cars have sported the numbers on track.

“Both the number 6 and number 7 have a rich tradition and history with Team Penske, and we want to build on that legacy as we begin this new journey with the Porsche Penske Motorsport program,” he said. “Car No. 6 delivered the very first victory for Team Penske with a class win at the 24 Hours of Daytona more than 56 years ago, so we are excited to carry the tradition forward.”

The Porsche 963 will try to prove it’s worthy of the historic numbers starting in 2023. The cars will make their official competition debut at the 24 Hours of Daytona in January.