Few design challenges contribute more to the success of a racing car than a low centre of gravity. The lower the centre of gravity, the less its transfer of weight to the outside tyres on corners and the less its transfer of weight forward under braking. Keeping the mass of the car as low as possible helps the designer make best use of the traction available all four tyres.
Flat or horizontally opposed vee engines represent the lowest possible configuration, placing their mass just above the road surface. Such engines were seldom practical in the front-engined racing car era, because their width would come into contact with the steering lock. But when rear-mounted engines became popular, the opportunity arose to employ flat-opposed engines.
The first racing car to compete using a flat-12 engine was a Ferrari: the 512 F1 in October 1964.
The flat-12 engine really achieved its full potential, however, in the 312B in 1970, and enjoyed an 11-year career in both Formula 1 cars and sports prototypes. In 1971 it delivered 470 bhp at 12,600 rpm and in the 1976 season it became the first engine of the unblown 3-litre generation to deliver 500 bhp at 12,200 rpm.
This ‘boxer’ engine, which performed so well for Ferrari on the track, was destined to have a road application – one which made Ferrari the first (and so far, only) car manufacturer to offer a series-produced car with a flat-opposed 12-cylinder engine. This was, and remains, a remarkable innovation.
A completely new 4.4-litre flat-12 engine was placed behind the driver and passenger in the new 365 GT4 BB (Berlinetta Boxer), which was first shown in prototype form at the Turin Salon in November 1971 and entered production in 1973.
In 1976, this exciting Ferrari was substantially redesigned and re-launched as the 512 BB. Its larger engine (4,943 cc) endowed it with more flexible performance and confirmed its position as one of the most desirable of the exotic sports cars.
The 512 BB was further refined into the Ferrari Testarossa that took the ‘boxer’ concept into the 1990s. Only replaced when a new generation of V12 cars was introduced, the Testarossa completed a third decade of innovative 12-cylinder flat-opposed engines for Ferrari.