The 1979 Champion Spark Plug 400, the 21st race of the NASCAR Winston Cup season, was held on August 19 at Michigan International Speedway before 60,000 fans. A 36-car field contested 200 laps on the two-mile oval. David Pearson, substituting for the injured Dale Earnhardt in the Osterlund Chevrolet, won the pole with a speed of 162.992 mph.
Richard Petty started fifth in the STP Chevrolet and won by one second with a last lap pass over Buddy Baker. Benny Parsons finished third followed by Pearson in fourth, and John Anderson fifth. Petty led nine laps, while Baker paced the field for a race-high 115. The race averaged 130.376 mph through five cautions for 35 laps and featured 21 lead changes. Petty earned $21,100 for the victory in what became a fuel-mileage battle.
