240
The 240 cu in (3.9 L) six for 1965–1970 full sized cars (continued to 74 in fleet models) and 63-77 trucks or vans produced 150 hp (112 kW). In stationary service (generators and pumps) fueled by LPG or natural gas, this is known as the CSG-639. The 240 had a bore of 4" and a stroke of 3.18".
Read more about this topic: Ford Straight-6 Engine, Fourth Generation