A random inspection at the Calexico border crossing resulted in the confiscation of a record $33.6 million worth of cocaine Friday night, officials said. Customs inspectors and drug-sniffing dogs found 960 pounds of cocaine in the trunk of a 1981 Chevrolet Caprice, said Bobbie Cassidy, spokeswoman for the U.S. Customs Service. It was the largest load of cocaine ever discovered there, Cassidy said. The inspectors and the dogs were checking 20 cars, which had been randomly selected for secondary inspection, when the driver of the Caprice ran back to Mexico, Cassidy said. A narcotics dog then scratched the car, signaling to the inspectors that drugs were in the vehicle. The cocaine was wrapped in 263 bricks, Cassidy said. Customs district officers have seized 3,675 pounds of cocaine during fiscal year 1992, which began Oct. 1. On Friday, U.S. Border Patrol agents seized 300 1-kilogram bricks of cocaine worth about $10 million at a checkpoint near Temecula, authorities said. On Tuesday, agents found 656 pounds of cocaine, worth another $10 million, after stopping a car on Pala Road near the Temecula checkpoint, officials said.