The original engine displaced 2.5 L; 152.1 cu in (2,492 cc) and produced 158 PS (116 kW; 156 hp).
It was a 2-valve-per-cylinder design with a single belt-driven camshaft per cylinder bank and six carburettors.
The engine has a bore and stroke of 88 mm × 68.3 mm (3.46 in × 2.69 in).

The Bosch L-Jetronic fuel injection was added for the 1983 Alfa 6, which produced the same 158 PS (116 kW; 156 hp).
The 2-valve engine ended its life in the Alfa 155, where there were two series for this engine, the 2.5 L; 152.1 cu in (2,492 cc) developing 166 PS (122 kW; 164 hp).
Differences between them were small and only on torque and power delivery producing exactly the same horsepower.

Applications:
1979–1986 Alfa Romeo Alfa 6
1980–1986 Alfa Romeo GTV6 (Alfa Romeo Alfetta GTV6 2.5)
1984–1987 Alfa Romeo 90
1985–1991 Alfa Romeo 75/Milano
1992–1997 Alfa Romeo 155
1985–1996 Fiat Croma
1987–1989 Rayton Fissore Magnum V6
1982 AC 3000ME MkII Prototype
The original engine displaced 2.5 L; 152.1 cu in (2,492 cc) and produced 158 PS (116 kW; 156 hp). It was a 2-valve-per-cylinder design with a single belt-driven camshaft per cylinder bank and six carburettors. The engine has a bore and stroke of 88 mm × 68.3 mm (3.46 in × 2.69 in).
The Bosch L-Jetronic fuel injection was added for the 1983 Alfa 6, which produced the same 158 PS (116 kW; 156 hp). The 2-valve engine ended its life in the Alfa 155, where there were two series for this engine, the 2.5 L; 152.1 cu in (2,492 cc) developing 166 PS (122 kW; 164 hp). Differences between them were small and only on torque and power delivery producing exactly the same horsepower.
Applications:
1979–1986 Alfa Romeo Alfa 6
1980–1986 Alfa Romeo GTV6 (Alfa Romeo Alfetta GTV6 2.5)
1984–1987 Alfa Romeo 90
1985–1991 Alfa Romeo 75/Milano
1992–1997 Alfa Romeo 155
1985–1996 Fiat Croma
1987–1989 Rayton Fissore Magnum V6
1982 AC 3000ME MkII Prototype
Alfa Romeo V6 engine