Terry Labonte held off Tim Richmond to win the American 500 in Rockingham, N.C., but perhaps he should have been satisfied merely to finish. There were several major crackups, and the race was slowed by 10 caution flags for a total of 64 laps on the 1.017-mile track.

Labonte, driving a Chevrolet, won by about two seconds over Richmond, who was in a Pontiac. Labonte averaged 119.324 mph. Among those involved in accidents were Cale Yarborough, Kyle Petty, Harry Gant and Richard Petty. Darrell Waltrip finished fifth and gained 40 points on Winston Cup leader Bobby Allison, who is ahead by 27 with two races left . . .

Sources told United Press International that Darlington (S.C) International Raceway officials plan to move the Southern 500 NASCAR grand national race to Sunday from its traditional Labor Day weekend Monday date. Track owners apparently plan to take advantage of a change in South Carolina law allowing races and other sports attractions on Sunday . . .

Jamie Tomaino of Neptune, N.J., took over on the 240th lap when George Kent ran out of gas and won the 250-lap Modified half of the $110,000 Cardinal 500 Classic doubleheader at Martinsville (Va.) Speedway. Sam Ard of Asheboro, N.C., won the Late Model Sportsman.