In Italian it is known as the "bialbero" ("twin-shaft"), and has also been nicknamed the "Nord" (North) engine in reference to its being built in Portello, Milan (later Arese, close to Milan), in the North of Italy and to distinguish it from the Alfa Romeo Boxer engine built in the South (Sud) for the Alfasud.

The diameter of the valve stems had been increased by 1 to 9 mm (0.04 to 0.35 in), the bore centre spacing was different, the timing chain longer and the crankshaft had been revised, among other changes.

[6] Additional changes to this version included offsetting the big-end bearings on the connecting rods, and adding sodium-filled exhaust valves.

[5] While this was an aesthetic loss it may have been beneficial in other ways, as some owners reported that the old sump kept the engine and oil so cool that in cold weather it was sometimes necessary to block off the radiator airflow to raise the coolant temperature enough for the interior heater to be effective.

[5] The Twin Cam was the first production automobile engine to employ a form of Variable Valve Timing (VVT).

Some Autodelta cylinder heads had an included angle between the intake and exhaust valves narrower than the 80° used in the majority of the production engines.

Built by Autodelta, the 1,567 cc (1.6 L) Twin Cam engine was boosted by two superchargers driven by an engine-powered oil pump.

The 2 litre engine was augmented by a KKK turbocharger blowing through a pair of Dell'Orto DHLA40H pressurised carburetors and produced 150 bhp (152 PS; 112 kW) in normal tune.

Equipped with a 1,962 cc (2.0 L) Twin Cam, dual carburetors and an Alfa Avio turbocharger the engine produced 125 kW (170 PS; 168 bhp).

[11] In 1986, a turbocharged version of the 1,779 cc (1.8 L) single-plug engine developing 167 PS (123 kW; 165 bhp) was used to create the Alfa Romeo 75 1.8 Turbo Quadrifoglio.

[5] The Twin Spark engine in the 75 also employed Alfa's variatore di fase VVT system which, when combined with electronic fuel injection, gave a power output of 148 PS (109 kW; 146 bhp).