The 1991 Daytona 500 By STP was a Winston Cup (now Sprint Cup) event held at Daytona International Speedway on February 17, 1991. It was the season opener. Ernie Irvan began a Morgan-McClure Motorsports restrictor plate-track dominance by winning NASCAR's biggest event, holding off Sterling Marlin under caution. The race was shown live on TV on CBS. Stats