INDY 500
Porsche's turbocharged Type 935/72 flat-six was coming along nicely for the company's 1979 campaign at Indianapolis in partnership with the ambitious Interscope team and its ace driver, Danny Ongais. Allowable boost pressures, however, had been coming down to curtail-rising speeds at the oft-dangerous quad-oval. For Porsche, no single issue was more crucial than the boost pressure at which the Porsche engine would be allowed to compete.
Boost pressures were an issue in a controversy between racing rule maker, United States Auto Club (USAC), and a group of team owners banded together in the summer of 1978 to form Championship Auto Racing Teams, Inc. (CART). These concerned individuals were worried about USAC's inclination to penalise their new Cosworth engines by forcing lower boost pressure in order to help the poorer Offenhauser-powered teams, who couldn't afford these costly new British powerplants. Porsche stepped right into this scenario.
When, in 1979, CART teams rebelled and started their own racing series, the stage was set for the eventual isolation of Indy 500 as the only major race sanctioned by USAC. The FIA-linked Sports Car Club of America (SCCA) accredited CART's racers, allowing them to compete in international events, such as the Indianapolis race. In the autumn of 1979, when Interscope and Porsche were beginning to test, the racing outlook for 1980 was uncertain at best. CART teams were those most likely to be friendly to Porsche's entry, but USAC was bidding fair to continue its rule of the famous Speedway. There, USAC showed itself to be less than steadfast, making several changes in rules and interpretations of rules during qualifying for the 1979 Indy 500.
For 1980, USAC allowed four-cylinder racing engines — the Offys — a boost of sixty incheseight inches or 9.3psi. USAC was entirely at liberty to set pressures as it wished. What would it specify for a six-cylinder engine? None had sought to compete since the Bardahl-Ferrari in 1956. Moreover, sixes had only won twice, namely the first race in 1911 (Marmon) and again in 1946 (Sparks-Thorne).
