 Complete the following phrase:  Drivers raced identically-prepared stock cars set up by a single team of mechanics in an effort to make the race purely a test of driver ability. It was run with a small field of 12 invited drivers. It was created and developed in 1972 by David Lockton, the developer of the Ontario Motor Speedway, launched in 1973, with Mark Donohue being the first driver to win the championship in 1974. The cars used that year were Porsche Carrera RSRs. Donohues win in the fourth and last race of that season was his last win, as he died in a Formula One crash at the Österreichring in practice for the 