Donohue developed a strong rapport with Penske’s chief mechanic, Karl Kainhofer. They didn’t restrict themselves to Can-Am racing: Penske and Donohue competed in the SCCA Trans-Am series in its heyday in the late ‘60s and developed cars to enter in the 24 hour sports car races at Daytona and Le Mans. They also later branched out into NASCAR.
Penske Racing’s first Indianapolis appearance came in 1969 with a Lola-Offenhauser. Donohue finished seventh in the Sunoco-sponsored car, claiming “Rookie of the Year” honors. A year later, Donohue finished second at Indianapolis, this time in an updated Lola with Ford power.
That winter, Donohue and Penske decided to switch to McLaren chassis for 1971. The new McLaren M16 adapted Formula 1 technology to Indy cars, including a wedge-shaped chassis with side-mounted radiators. In addition, McLaren cleverly bypassed a rule that banned front and rear wings by integrating them into the central bodywork.
“The minute I saw it I knew McLaren had a better package than what we were discussing with Lola,” Donohue wrote in his autobiography The Unfair Advantage. “They had obviously learned a lot about wings in Formula 1 and were applying that knowledge to Indy. I quietly marveled at their guts to come up with such a new concept, and it inspired me even more to go USAC racing.”