Chapman initially chose the Ford 105E inline four used in the Ford Anglia as the basis of this new engine. The 105E displaced and had a cast iron block produced with Ford's thin-wall casting process, resulting in a relatively light part. While the 105E block only provided three main bearings for the crankshaft, the oversquare design kept piston speeds down and gave room for larger valves in the new cylinder head. When the larger 109E for the Ford Consul Classic was released, it became the platform for most of the development of the new Lotus engine.