The peak years of his career began in 1957, with a move from Alfa to Ferrari: ‘Il Commendatore’ Enzo Ferrari personally took the young engineer to Maranello, a decision which paid huge dividends. As a development manager, designer, test driver and chief engineer, Bizzarrini influenced not only the development of the Ferrari 250 Testa Rossa and the Ferrari 250 GT SWB, but he also designed the world-famous Ferrari 250 GTO. Yet as well as being a brilliant engineer, Bizzarrini valued his freedom – and in 1961 he was one of the instigators of the Ferrari ‘palace revolution’. He became part of Automobili Turismo e Sport (ATS)), a company started by the ex-Ferrari engineers to build a Formula 1 single seater and a GT sport car, the A.T.S. Serenissima. One of ATS's financial backers, Count Giovanni Volpi, owner of Scuderia Serenissima, hired Bizzarrini to upgrade a Ferrari 250 GT SWB, with chassis number #2819GT to GTO specifications. This resulted in the Ferrari 250 GT SWB Drogo also known as the "Breadvan". Bizzarrini's engineering company, Societa Autostar, was commissioned to design a V-12 engine for a GT car to be built by another dissatisfied Ferrari customer, Ferruccio Lamborghini. Lamborghini considered the resulting engine to be too highly strung, and ordered that it be detuned.
Bizzarrini worked since 1964 for Iso Rivolta and developed three models: Iso Rivolta GT, Iso Grifo both A3L and A3C versions. His work was to develop a pressed steel frame chassis for Iso cars.