SALT LAKE CITY - A British pilot broke a land-speed record for driving with a diesel engine, racing across the Bonneville Salt Flats at more than 325 mph.

Andy Green broke the supercharged diesel streamliner world record by more than 90 mph by reaching an average land speed Tuesday of 328.767 mph. The old record was 235.756 mph, set by Virgil Snyder on the Bonneville Salt Flats in 1973.

"It's absolutely astonishing what we've achieved today," Green said by telephone from the salt flats, about 90 miles west of Salt Lake City.

The attempt was observed by the FIA, the international governing body of racing. FIA rules require that two passes be made within an hour to arrive at an average speed. Green's first run was clocked at 324.265 mph and his return run at 333.364 mph, said David Petrali, FIA's representative at the 11-mile track.

Green drove a vehicle powered by two diesel engines that have a combined total of 1,500 horsepower. Each is a 4-cylinder, 4.4-liter engine used commercially as a backhoe loader.

Green said he used only about 1,200 horsepower because the vehicle couldn't handle any more than that. The tires on the car are designed to go no faster than 350 mph, but Green's crew said the car is capable of going 400 mph.

The record will likely become official when a FIA board meets next month. Green said he might try to break his own record this week.

Green also set a supersonic world land speed record in 1997 at 763.035 mph using a jet engine.