Lancia Flat-4 engine

The original version was the 1.5 L (1,500 cc; 91.5 cu in) introduced in 1960; it used an 82 mm × 71 mm (3.23 in × 2.80 in) bore and stroke. It was revised on 1963 with a smaller 80 mm (3.15 in) bore and a longer 74 mm (2.91 in) stroke, thus displacing 1.5 L (1,488 cc; 90.8 cu in). A final version was introduced in 1967 with an even longer 80 mm (3.15 in) stroke coupled with a 77 mm (3.03 in) bore, giving a displacement of 1.5 L (1,490 cc; 90.9 cu in). Production ceased in 1970.

The first 1800 was a 1.7 L (1,727 cc; 105.4 cu in) introduced in 1962. It used an 88 mm × 71 mm (3.46 in × 2.80 in) bore and stroke. One year later it was replaced by a true 1.8 L (1,800 cc; 109.8 cu in) engine thanks to a longer 74 mm (2.91 in) stroke. In 1967 appeared the 1.8 L (1,816 cc; 110.8 cu in) version using an 85 mm × 80 mm (3.35 in × 3.15 in) bore and stroke.

The 2.0 L (1,991 cc; 121.5 cu in) 2000 version was the ultimate Flavia engine. Bore and stroke was 89 mm × 80 mm (3.50 in × 3.15 in) for a good oversquare ratio. In 1971, the 2.0 L produced 115 bhp (86 kW; 117 PS),^{[citation needed]} and in the HF Coupé in 1972 it produced 125 bhp (93 kW; 127 PS). This engine was produced from 1968 through 1974.

Lancia developed the large light-alloy overhead camshaft 2.0-litre and 2.5-litre flat-4 engines specifically for the Lancia Gamma, rather than using Fiat derived engines as used in the Beta and Montecarlo and were in production between 1976 and 1984.

Replacing the 2.0 L pushrod engine used in the Flavia, the new 2.0 L (1,999 cc; 122.0 cu in) OHC engine produced 120 bhp (89 kW; 122 PS) at 5500 rpm^[2] and 172 N⋅m (127 lb⋅ft) of torque at 3500 rpm.

The 2.5 L (2,484 cc; 151.6 cu in) engine was initially available with twin-choke Weber carburetors, but in the last few years of production it was equipped with fuel injection. In both forms, it produced 140 bhp (104 kW; 142 PS) at 5400 rpm and 208 N⋅m (153 lb⋅ft) torque at 3000 rpm.^[3]