Driver Andy Green hit 328.767 mph on the Bonneville Salt Flats in the United States in the JCB Dieselmax on Tuesday, before setting the new record on Wednesday.
The previous record for a diesel car, 235.756 mph, was set in 1973 by Virgil Snyder in the Thermo King Streamliner.
JCB Dieselmax spokesman Jonathan Gill told Reuters he did not expect the team to try again.
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The vehicle is powered by two specially tuned diesel engines normally found in JCB diggers and tractors.
Boasting twin JCB444 common rail injection diesels with turbochargers and intercoolers, the JCB Dieselmax generates an impressive 750 bhp at 3,800 rpm.
At just over nine metres long, the sleek vehicle has a drag co-efficient of 0.174 cd -- which compares with a typical family saloon's drag co-efficient of about 30 cd.
Green is no stranger to speed. Not only is he a Royal Air Force jet pilot, but he holds the overall land speed record of 763 mph, set in 1997 with the jet-propelled ThrustSSC car.