The relatively heavy but elegant 2600 series with a higher engine power was developed as the successor to the 2000 series. In order to accommodate the much larger 2600’s engine, the Italian car manufacturer slightly modified the 2000’s bodywork. Carrozzeria Touring built the open, sporty Spider 2+2 seater, while the four-door luxurious Berlina sedan was built at the Portello plant. Giorgetto Giugiaro had designed the sparkling, two-door Coupé Sprint that Bertone produced.
The 2600 OSI, an elegant limousine with particularly luxurious features, was only available for a short period of time, from summer 1965 to autumn 1967. Simultaneously with the OSI, the Sprint Zagato was launched, another sporty coupé of the 2600 series with improved equipment, material quality and workmanship. What all models had in common was the high safety standard and a newly developed, flexible and powerful engine. This 2.6-litre in-line six-cylinder engine made of aluminium had two overhead camshafts and, for the Berlina, two and for the other models, three carburetors. The engines at the Berlina delivered 130 hp and allowed a top speed of 175 km/h, the Sprint and the Spider pulled 145 hp from the modern drive and reached a top speed of 200 km/h. The engine was equipped with a new engine. In addition, the vehicles were equipped as standard with a synchronized five-speed transmission, and the disc brakes on the front wheels provided improved braking performance, starting in autumn 1963, as part of the model upgrading, also on the rear wheels. Due to the relatively high price, however, the Alfa Romeo 2600 could not hold its own. In total, only 105 vehicles from the Sprint Zagato, the OSI 53, the Berlina 2038, the Spider 2255 and the Sprint 6999 ran off the assembly line, but the figures differ depending on the source.