The 1979 Champion Spark Plug 400 was a NASCAR Winston Cup Series racing event that took place on August 19, 1979, at Michigan International Speedway in Brooklyn, Michigan. Only manual transmission vehicles were allowed to participate in this race; a policy that NASCAR has retained to the present day. Michigan International Speedway had been a Mercury-dominated track from 1969-78 before its driving style became neutral to all manufacturers. It was also a track that suited a smooth driver or a driver that could change his driving tactics for Michigan International Speedway.