Original sentence: Initially, the Mark 1 was offered with a 2.4 litre, 112 bhp, short-stroke version of the XK120's twin-cam six-cylinder engine, but from 1957 the larger and heavier 3.4 litre 210 bhp unit already used in the larger Jaguars also became available, largely in response to pressure from US Jaguar dealers
Edited sentence: Initially, the Mark 1 was offered with a 2.4 litre short-stroke version of the XK120's twin-cam six-cylinder engine, rated at 112 bhp gross, but from 1957 the larger and heavier 3.4 litre 210 bhp unit already used in the larger Jaguars also became available, largely in response to pressure from US Jaguar dealers