The Ferrari 312T was a Ferrari Formula One car design, based on the 312B3 from 1974. In various versions, it was used from 1975 until 1980. It was designed by Mauro Forghieri for the 1975 season, and was an uncomplicated and clean design that responded well to mechanical upgrades. The 312T series won 27 races, four Constructors' and three Drivers' Championships, making it the most successful car design in Formula One history. It was replaced for the 1981 season by the 126 C, Ferrari's first turbocharged F1 car. It was also Ferrari's last naturally-aspirated F1 car until the Ferrari 640 in 1989, after the ban on turbocharged engines. Mechanical configuration The car was powered by the powerful and reliable Tipo 015 flat-12 engine which gave around 510 bhp. Although it had to carry more fuel, oil and water than the Cosworth DFV-powered cars the power-to-weight ratio of the flat-12 was about the same as the DFV. The "3" stood for the car's engine displacement (3 litres) and "12" was the number of cylinders it had (12). In order to improve upon the preceding 312B3, Forghieri designed a new chassis for the 312T. The 312T chassis was a semi-monocoque consisting of tubular spaceframe reinforced with riveted aluminium panels. This "traditional" construction was a departure from the full monocoque of the 312B3. The new chassis was slightly heavier than the 312B3 monocoque, but had comparable rigidity and was easier to adjust and repair. It could also accept bodywork with a lower frontal area, reducing drag. The suspension design was substantially revised to work with the new chassis. The same basic chassis design and construction method was used in all 312T-series cars, although later cars received modifications to improve torsional rigidity. Forgheri and Ferrari engineer Walter Salvarani also developed a new gearbox for the 312T. This unit was mounted behind the engine in a transverse orientation, ahead of the rear wheels. This moved the car's center of mass forward and lowered the polar moment of inertia. This design had precedent in the March 721X. This gearbox configuration was considered so important to the overall design that the "T" in the 312T name stood for trasversale, Italian for transverse. While all 312T gearboxes used in competition were conventional manual transmissions, Ferrari briefly experimented with a semi-automatic version of the gearbox in 1979. This consisted of a modified version of the manual gearbox actuated by