From 1971 to 1983, he was the official engine preparation expert for Porsche, with many victories in 24 Hours of Le Mans, French Rally Championship and European Rally Championship. Notably in 1972, Assisted by Jürgen Barth, future winner in a Porsche 936 in 1977, by Sylvain Garant, then Mike Keizer. The 911 with a 2.5-liter engine, flanked by the No. 41 finished in 13th place in the general classification while winning its category.