Paolo Barilla, taking over after an accident forced defending champion Derek Bell into an extended pit stop, drove his Porsche 962 to victory yesterday in the $250,000 Miami Grand Prix.

Barilla, of Italy, drove in a team with Bob Wollek of France and finished well ahead of second-place Danny Sullivan in a Porsche 962. Hans Stuck finished third in a 962, and Hurley Haywood fourth in a Jaguar XJR-7.

The win was worth $55,000 to Barilla and Wollek. Sullivan and partner A.J. Foyt collected $27,000. The three-hour race over the 1.87-mile course was run in front of an estimated 80,000 fans.

Bell had a 12-second lead over Wollek when the leader banged into Gianpiero Moretti's Porsche 962 on a turn, breaking the rear suspension in Bell's car with a little less than an hour left in the race. After the accident, Wollek let Barilla take over and Barilla opened a 48-second lead over second-place Stuck with 20 minutes to go . . .

Terry Labonte gained control early and easily won the Goodwrench 500 NASCAR stock car race at North Carolina Motor Speedway in Rockingham. He averaged 120.488 mph, won $44,550.

Labonte beat back challenges by Harry Gant, Daytona 500 winner Geoff Bodine, Dale Earnhardt and Richard Petty on the way to his sixth career victory and first of the season.

Labonte, the 1984 Winston Cup champion, led the 492-lap race six times for 304 laps, including the last 56. His Oldsmobile came in less than two car lengths ahead of Gant's Chevrolet. The only other car on the lead lap at the end was the Pontiac of Petty, who ran the last third of the race with no brakes.