At the time of the Miura, participation in competitions had always been excluded from Lamborghini. Despite this, test driver Bob Wallace obtained permission to develop a racing version of the Miura, provided he did it outside of working hours. The Miura Jota 4 was completed in late 1969 but was never officially presented. Equipped with the 4000cc 12-cylinder engine, the Jota 4 had a power of 440 horsepower and a weight of 890 kg. Aesthetically it was distinguished by a whole series of aerodynamic improvements and the enlarged bodywork. The car completed several tests between 1970 and 1971, including on the Pirelli private track in Milan. The only authentic model of the Jota appears to have been sold and destroyed in an accident by its owner. Some Lamborghini customers, having seen the photos of the Jota 4, wanted to have their Miuras adapted according to the competition specs. There are six examples around, called the Miura P400 SVJ, officially adapted by Lamborghini.