Sunday 21st January 1973
Mark Donohue drove Roger Penske’s AMC Matador to victory in the NASCAR Grand National Western 500 at Riverside International Raceway. The Matador was equipped with disc brakes on all four wheels. Donohue, who led 138 of the 191 total laps, took the lead to stay on lap 117 and won by more than a lap. Bobby Allison’s Chevy was 2nd with GN West champ Ray Elder, Bobby Unser and GN West driver Jim Insolo rounding out the top five. The win was the first and only NASCAR GN win for Donohue, and came in only his fifth NASCAR start.