'The 3.4-litre Jaguar Engine is one of the marvels of the age. In racing tune, it achieves tremendous speeds, and in normal form it powers a range of cars from six-seater luxury models to the sports XK types. Now, a "hotter" version of this basic engine has been made available, and it is used in the ultra-high speed XK 150S two-seaters.' ? John Bolster, Autosport.
What would turn out to be the final glorious incarnation of Jaguar's fabulous 'XK' series of sports cars arrived in 1957. As its nomenclature suggests, the XK150 was a progressive development of the XK120 and XK140, retaining the same basic chassis, 3.4-litre engine and four-speed Moss transmission of its predecessors while benefiting from a new, wider body that provided increased interior space and improved visibility courtesy of a single-piece wrap-around windscreen, replacing the XK140's divided screen. Cleverly, the new body used many XK120/140 pressings, the increased width being achieved by means of a 4"-wide central fillet. A higher front wing line and broader radiator grille were other obvious differences, but the new model's main talking point was its Dunlop disc brakes. Fade following repeated stops from high speed had been a problem of the earlier, drum-braked cars, but now the XK had stopping power to match its prodigious straight-line speed.
Introduced in the spring of 1957, the XK150 was available at first only in fixed and drophead coupé forms, the open roadster version not appearing until the following year. At 190bhp, the engine's maximum power output was identical to that of the XK140, so performance was little changed. 'Special Equipment' and 'S' versions came with 210 and 250bhp respectively, the latter delivering an astonishing 0-60mph time of 7.3 seconds and a top speed of 136mph. This was achieved by the introduction of the Weslake-developed 'straight-port' cylinder head, high-compression pistons, triple 2" SU carburettors and twin electric fuel pumps. Overdrive and a Borg-Warner automatic gearbox were the transmission options, the latter becoming an increasingly popular choice, while a Thornton Powr-Lok limited-slip differential was available for the XK150 'S'. Steel wheels remained the standard fitting, though XK150s so equipped are a great rarity, as most were sold in SE (Special Equipment) specification with centre-lock wire wheels. The much-admired chromed Jaguar mascot was made available as an optional extra on an XK for the first time.
Bolster concluded his review thus: 'It combines extreme performance with perfect manners to a quite exceptional degree, and it has a sporting appearance that is entirely suitable for the most formal occasions. Being a Jaguar, it is really hardly necessary to remark that it represents outstanding value for money.'
It is estimated that only 88 right-hand drive examples of the XK150 'S' 3.4 fixed-head coupé were built, making it one of the rarest of all the variants of this most iconic of post-war British sports cars. Chassis number 'T824946DN', registration number 'YOP 911', was completed in February 1959 as a UK-market, right-hand drive, 3.4-litre 'S' fixed-head coupé finished in Cotswold Blue. It is equipped with the desirable manual/overdrive transmission and has the high (4.09:1) rear axle ratio for relaxed cruising at high speeds. According to the Heritage Certificate, this XK was sold through Jaguar main agents P J Evans of Birmingham to its first owner, Mr J Kitchen of Sutton Coldfield. The old-style VE.60 continuation logbook lists a number of owners up to 1975 when the car was taken off the road. Its last tax disc, valid to December 1975, is still in place on the windscreen.
Offered from long-term private ownership, 'YOP 911' has remained in storage since 1975 but nevertheless has been started periodically and runs and drives well (tested at low speeds on private land) with good oil pressure and the gears and clutch operating well. This 'matching numbers' car has never been fully restored nor indeed ever had a colour change; after 43 years of slumber it now requires full restoration and offers an exciting opportunity to renovate an entirely original example of a very rare model.