There were a total of five 250 GT SWB Sperimentale created. The first was chassis number 2429GT and fitted with a modified Comp/61 engine though it was never raced. The second car was 2643GT which received a 3-liter V12 featuring a dry-sump lubrication system and six carburetors. This car would later be known as the 250 GTO prototype, as it shared many similarities to the legendary 250 GTO.
This car with chassis number 2643GT was built in 1961 as a styling and engineering exercise for Ferrari's racing interests. Often referred to as the GTO prototype, it combined a modified 250 SWB chassis with a Type 168/61 Testarossa spec dry-sump engine. The car was used for a development work by the factory. The car ran (in its current blue livery) as a factory entry at LeMans in June of 1961 with Fernand Tavano and Giancarlo Baghetti driving. It was very unstable at speed on the Mulsanne, which necessitated the rear spoiler and the front winglets that are on the car now. These were somewhat hastily added to the car between practice and the race. It retired with engine trouble. The car's greatest accomplishment came in February 1962, at Daytona, where, with Stirling Moss at the wheel, it placed first in class in a three-hour race.
Over the years the car has changed hands several times, until coming into possession of its current owner, who commissioned a restoration bringing the car back to its original blue 1961 LeMans livery. The owner actively campaigns it in historic competition and has entered it in concours d'Elegance events.