The XJ line received a facelift in Autumn 1973 for the 1974 model year, thereafter known as the "Series II"; retrospectively the earlier cars were referred to as the "Series I". The 4.2 L XJ6 straight-6 engine (most popular in the United Kingdom) and the 5.3 L V12 XJ12 were continued with an addition of a 3.4 L (3,442 cc (210.0 cu in)) version of the XK engine available from 1975. The Series II and Series II coupé were the last Jaguar models with direct input by Sir William Lyons before his retirement.