When did engine capacity start being measured in CC?

[Bob Culver]

It is customary to attribute long stoke engines to the RAC tax but American cars were in the same ratio. The tax certainly kept Brit cars puny. According to my father, 1920s Brit cars here crawling up hills were generally regarded as a bit of a joke. Long strokes moderate loads on white metal bearings at modest revs, and enable higher c.r. Can be more efficient with reduced emissions and have made a bit of a comeback. Moderns spend most of time at very modest revs.