Launched in 1966, the Jaguar 420 was the final incarnation of Jaguars amazingly successful medium-sized saloon line that had commenced way back in 1955 with the MkI. The newcomer was, in fact, a face-lifted S-Type, the latters Mk2-style front end having been replaced by one reminiscent of the MkX. A development of the hugely successful Mk2, the S-Type/420 differed mechanically by virtue of its independent rear suspension, the latter first seen in saloon form on the MkX. The 4.2-litre XK six-cylinder engine was standard on the 420, which incorporated other improvements such as alternator electrics, a limited-slip differential and dual-circuit brakes. Despite possessing superior handling and greater range than the Mk2, the S-Type and Jaguar 420 have lived in the shadow of their illustrious predecessor and tend to be undervalued even today.