Lancia, known for their advanced engineering, surprised the auto world by designing a new aluminum flat-4 engine for their 1961 Flavia. Though it was a pushrod engine, it was advanced for the time. The Lancia boxer was only ever used in the Flavia.
The original version was the 1.5 L (1488 cc) 1500.
The 1.8 L 1800 was introduced in the mid-1960s. It used an 88 mm bore and 74 mm stroke and produced up to 102 hp (76 kW) with Kugelfischer mechanical fuel injection.
The 2.0 L (1991 cc) 2000 version was the ultimate Flavia engine. Bore was 89 mm and stroke was 80 mm for a good oversquare ratio. This engine was produced from 1968 through 1974.