An assistant to the great Vittorio Jano at Alfa Romeo in the 1920s and early 1930s, Colombo designed the 158 engine for the 1937 Alfetta at the request of Enzo Ferrari. After the war Ferrari asked him to design the first Ferrari V12 engine. The rules at the time allowed for 1.5-liter supercharged engines but Colombo's was disappointing and so Aurelio Lampredi designed a 4.5-liter unit to replace it. In 1950 Colombo went back to Alfa Romeo and oversaw the world championships of Nino Farina in 1950 and Juan-Manuel Fangio in 1951. In 1953 he moved to Maserati and designed the 250F - one of the great Grand Prix cars of history. In 1955 he moved on to Bugatti which was trying to revive its fortunes with an F1 program but the mid-engined 251 was not a success when it appeared in 1956.