A four-valve version was introduced in 1997 with the Alfa Romeo 156.
The engine now produced 190 PS (140 kW; 187 hp).
In 2001, the V6 was uprated to 192 PS (141 kW; 189 hp).
The 166 used a slightly detuned version to make more low rev torque.
This engine version was awarded as the International Engine of the Year in 2000.
The engine has a bore and stroke of 88 mm × 68.3 mm (3.46 in × 2.69 in), the same as the two-valve.

Applications:
1996–2005 Alfa Romeo 156
1996–2007 Alfa Romeo 166
A four-valve version was introduced in 1997 with the Alfa Romeo 156. The engine now produced 190 PS (140 kW; 187 hp). In 2001, the V6 was uprated to 192 PS (141 kW; 189 hp). The 166 used a slightly detuned version to make more low rev torque. This engine version was awarded as the International Engine of the Year in 2000. The engine has a bore and stroke of 88 mm × 68.3 mm (3.46 in × 2.69 in), the same as the two-valve.
Applications:
1996–2005 Alfa Romeo 156
1996–2007 Alfa Romeo 166
Alfa Romeo V6 engine