Richard Petty, who was knocked unconscious when he wrecked his Pontiac during practice Friday, plans to start today's $716,225 Coca-Cola 600 NASCAR Winston Cup stock car race in another car.

"We're going to try to finish," said Petty, who will be starting 37th in D.K. Ulrich's Chevrolet in the race at Charlotte Motor Speedway in Harrisburg, N.C. "I don't think we'll run with the leaders. I don't know how good the car is or how good I'll able to drive it. We're basically going to try to go out and finish the best we can."

He spent Friday night in a hospital with a concussion after he crashed his Pontiac, which had qualified for a No. 15 starting spot. He said his right front tire blew out, causing him to slam against the wall at turn 3.

"I was dropping into the corner and turning the car," he said. "I was turning it more and more, and the car kept going straight. I said, 'This is going to hurt.' I don't remember anything after that till I woke up in the hospital."

Petty said that he might be too sore to finish the 600 miles and that Ulrich might drive some of them. By borrowing Ulrich's car, Petty continues a streak of 434 consecutive starts. With 200 career victories, he plans his 1,000th career start at the Miller American 400 next month in Brooklyn, Mich. . . .

Tim Richmond outlasted Dale Earnhardt and Darrell Waltrip to win the Winn-Dixie 300 NASCAR Grand National at Charlotte Motor Speedway and become the first consecutive winner in the race's nine-year history. Richmond drove his Pontiac a record average speed of 139.715 mph in winning $37,200 . . .

In Spa-Francorchamps, Belgium, Nelson Piquet, in a Williams-Honda, took the pole for today's Belgian Grand Prix.

TENNIS

Henrik Sundstrom beat Emilio Sanchez to join top-seeded Andres Gomez in the final of a $100,000 men's Grand Prix tournament in Florence. Sundstrom defeated Sanchez, 7-5, 7-6 (7-2), and today will face Gomez, who defeated 19-year-old Claudio Mazzardi, 2-6, 6-2, 6-3 . . .

In Lugano, Switzerland, No. 14 Raffaella Reggi upset sixth-seeded Bettina Bunge, 7-5, 3-6, 7-6 (7-2), to advance to the final of the women's $100,000 European Open. Reggi will face top-seeded Manuela Maleeva, who breezed past Sabrina Goles, 6-2, 6-3 . . .

Dan Goldie of McLean, Va., and Stanford University and Richey Reneberg of Southern Methodist won semifinal matches to advance to today's singles final in the NCAA men's championships in Athens, Ga.

Goldie, at No. 3 the highest-seeded player who survived until the semifinals, defeated No. 5 Brad Pearce of UCLA, 6-2, 7-6. Reneberg, seeded sixth, defeated Joey Blake of Arkansas, 6-4, 6-3.

FOOTBALL

Real estate syndicator Craig Hall, who has been trying to raise money to bail out 65 deals he says are in trouble, sold his 10 percent interest in the Dallas Cowboys to the team's major shareholders, officials said.

H.R. (Bum) Bright of Dallas and Ed Smith of Houston acquired Hall's interest in the team for an undisclosed price, said Tex Schramm, the team president and general manager. Schramm estimated the team's total value at $60 million, which would put Hall's share at $6 million.

The transfer was approved earlier in the week by the National Football Conference, an NFC spokesman said.

COLLEGES

An appeal by the University of Florida to reduce financial penalties levied against the Gators because of recruiting violations will be considered by Southeastern Conference officials meeting this week in Destin, Fla.

The spring meeting of the 10-member SEC begins today.

A 1978 SEC rule automatically prohibited Florida from sharing in bowl and television revenues. Florida, stripped of its 1984 SEC football crown by members meeting here last year, is the first SEC team excluded from revenue sharing under the 8-year-old rule. BOXING

Fredo Layne of Panama knocked out Wilfredo Gomez of Puerto Rico in the ninth round in San Juan, Puerto Rico, to strip Gomez of his World Boxing Association junior lightweight title.

RUNNING

Jeffrey Smith of Denver and Mary Sperry of South Burlington, Vt., each won $500,000 in the Super Run II 10-kilometer race in South Lake Tahoe, Calif. The field consisted of 99 qualifiers from all 50 states. Smith, winner of the men's division in 30:52, and Sperry, winner of the women's division in 37:58, will each receive $10,000 a year for the next 50 years from life insurance annuities, according to a spokesman for the sponsoring Stroh's beer company.

HOCKEY

Penguins owner Edward J. DeBartolo may seek a parking garage linked by a shuttle to the Civic Arena as a condition to keep the team in Pittsburgh for the next five years, city officials said.

Ronald C. Schmeiser, city finance director, said the proposal, estimated to cost $62 million, likely will be a topic of discussion when Mayor Richard Caliguiri meets Tuesday with DeBartolo's representatives to discuss DeBartolo's request for a one-year lease extension at the Civic Arena.

MISCELLANEOUS

Rob Stull, a 1984 Olympian from Damascus, Md., was tied with four-time national champion Mike Burley of San Antonio after the first day of the five-day Modern Pentathlon National Championships in San Antonio. Stull and Burley had a total of 1,040 points out of a possible 1,100 in the riding phase of the competition. Tara Hansler of Corpus Christi, Tex., had the only perfect ride of the day, scoring 1,100 points to lead the women's division.