Volvo's first six-cylinder engine was introduced in 1929. It was an side-valve straight-six engine.
- 1929–1958 side-valve six — PV651/2, TR671/4, PV653/4, TR676/9, PV658/9, PV36, PV51/2, PV53/6, PV801/2, PV821/2, PV831/2 and PV60
Read more about this topic: List Of Volvo Engines