The 1991 Champion Spark Plug 400 was the 19th stock car race of the 1991 NASCAR Winston Cup Series season and the 23rd iteration of the event.

[1][2][3][4] To fill out the top three, Penske Racing South driver Rusty Wallace would finish third.

It is known as a "sister track" to Texas World Speedway as MIS's oval design was a direct basis of TWS, with moderate modifications to the banking in the corners, and was used as the basis of Auto Club Speedway.

Michigan International Speedway is recognized as one of motorsports' premier facilities because of its wide racing surface and high banking (by open-wheel standards; the 18-degree banking is modest by stock car standards).

Alan Kulwicki, driving for his own AK Racing team, would win the pole, setting a time of 41.515 and an average speed of 173.431 miles per hour (279.110 km/h) in the first round.