The 1981 Champion Spark Plug 400 was a Winston Cup (now Nextel Cup) event held at Michigan International Speedway on August 16, 1981. Richard Petty led 64 of the 200 laps in route to his third and final victory of the year, holding off Darrell Waltrip by two carlengths. Points leader Bobby Allison led 15 laps before finishing 7th to keep his points lead on Waltrip at 70 points. Stats