The Lamborghini V-12 is a V12 engine designed by Lamborghini. This is the first engine ever produced by the firm. It is generally considered one of the finest automobile engines ever made. It first entered production in 3464 cc (3.5 liter) form in the Lamborghini 350 GT, the first car ever produced by the carmaker.
There are many versions of the story of its development - some say it is derived from a Honda F1 design, others say that Giotto Bizzarrini borrowed heavily from his own F1 design. Both were 1.5 liter V12 racing engines and the Lamborghini unit has similarities to both.
In any case, when Ferruccio Lamborghini set out to provide Ferrari with competition, he contracted Bizzarrini to design the engine for his car and, according to some accounts, paid him a bonus for every horsepower over what Ferrari's V12 could produce. The finished product was such that, with minor modifications and improvements, the very same engine (in 6.2 liter form) powers the current V12-engined Lamborghini Murciélago.
The engine was designed from the start to be a quad cam (two cams per cylinder-bank) 60° V12 - as an intentional snub by Mr. Lamborghini of Ferrari's single-cam per-bank design. When the 3464 cc prototype was tested in 1963, it was able to produce 370 bhp (276 kW) at 9000 rpm - a figure of almost 107 bhp (77 kW) per liter and unprecedented at the time. Bizzarrini famously insisted that the engine was mechanically capable of reaching an astonishing 400 bhp (298 kW) at 11000 rpm with an uprated fuel system but the design was judged adequate and when fitted with production carbs, all the auxiliary systems and detuned for road use, the engine still made an impressive 280 bhp (209 kW). For reference, compare the 3.5 liter V12 to the 3.7 liter V8 engine in the 1968 Chevy Camaro which produced 140 bhp (104 kW).
Over the years, the engine has nearly doubled in displacement, seen the modification of the heads to allow four valves/cylinder, the replacement of carbs with electronic fuel-injection and the replacement of a wet sump lubrication system with a dry sump one but the engine that powers the current Murciélago can trace its lineage back to the F1-inspired design of Bizzarrini and his team more than forty years ago.