Dale Earnhardt has been fined $10,000 by NASCAR for ignoring a black-flag warning during Monday's Busch Clash at Daytona (Fla.) International Speedway.

Officials said the fine is believed to be the largest in NASCAR history.

Earnhardt received a black flag--an order to leave the track--midway through the 20-lap event when his Ford started smoking and spewing oil. But he continued to race around the 2.5-mile track, also ignoring a second black flag, and NASCAR scorers stopped registering his laps after the first 18.

Earnhardt was credited officially with a 12th-place finish in a field of 16.

Meanwhile, the rear spoiler--a rigid piece of aluminum attached to the rear deck of a racer that is used to exert downward air pressure on the back of a car to help keep it on the track--is being blamed for the apparent instability of the Chevrolet Monte Carlo SS, which almost overnight has become the No. 1 choice of many top teams.

There is no question the Monte Carlo is fast. Cale Yarborough drove one Monday to the first 200-mile-per-hour lap ever recorded at Daytona by a stock car. But, the next time around the track, the car slammed into a concrete wall. Later Monday, in the Busch Clash, Bobby Allison's new Monte Carlo wound up a mass of junk after he bounced off two walls. In the same race, Terry Labonte's Monte Carlo whacked the wall almost head on, then spun off and took out two other cars.