The 1991 Heinz Southern 500 was the 21st stock car race of the 1991 NASCAR Winston Cup Series season and the 42nd iteration of the event.

It is of a unique, somewhat egg-shaped design, an oval with the ends of very different configurations, a condition which supposedly arose from the proximity of one end of the track to a minnow pond the owner refused to relocate.

This situation makes it very challenging for the crews to set up their cars' handling in a way that is effective at both ends.

For this specific race, positions 21-40 would be decided on time[5] and depending on who needed it, a select amount of positions were given to cars who had not otherwise qualified on time but were high enough in owner's points; up to two provisionals were given.

Davey Allison, driving for Robert Yates Racing, would win the pole, setting a time of 30.261 and an average speed of 162.506 miles per hour (261.528 km/h) in the first round.