Jaguar XK120: The Original Supercar

As World War II engulfed Europe in the early 1940’s, many automobile manufacturers ceased passenger car production to focus on the war efforts. Amongst them was SS Cars, the British company which began life as the Swallow Sidecar Company twenty years before. When they returned to building cars in 1945, owner William Lyons understandably felt that “SS” may perhaps no longer have the best connotations, so he renamed the brand after one its most successful pre-war models: the Jaguar. 

In October 1948, the freshly rebranded Jaguar Cars Limited sponsored a stand at the London Auto Show where it debuted its first ever sports car, dubbed the XK120. The swooping lines and low profile garnered immediate attention, and the very first example of this handsome and elegant roadster went to an appropriately handsome and elegant customer, Hollywood superstar Clark Gable. But the XK120 wasn’t just a pretty face, it was also the fastest production car in the world.

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Jaguar claimed the 120 in XK120 stood for its top speed in miles per hour, which itself would have clenched the accolade of fastest car on the market. But magazine testing at the time proved this to be untrue- it was actually capable of 124.6mph. This celebration would be short-lived however as a new record of 135mph was soon achieved by a different car: an XK120 with its removable windshield replaced with a lower windscreen and a tonneau cover over the passenger seat. 

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Briefly hitting a top speed is one thing, but the XK120 broke boundaries in endurance tests as well. At the hands of English racing legends Leslie Johnson and Stirling Moss the XK120 set a triumvirate of records, sustaining average speeds of 131.83mph for one hour, 107.56mph over 24 hours, and 100.7mph for seven straight days, the latter two including stops for fuel and tires. In 1953 an XK120 fitted with solely aerodynamic modifications would complete the flying mile at a then unimaginable 172.412mph.

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Unsurprisingly, the gentleman’s rocket ship that was the XK120 also enjoyed a storied career at the race track. Proving it was a true “race on Sunday, drive on Monday” masterpiece, race-prepped XK120’s enjoyed impressive results at Le Mans, Silverstone, Targa Florio, and the Mille Miglia. Al Keller even won a NASCAR race in an XK120 in 1954, marking the last time foreign cars were ever allowed in the series. 

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While the stock production version of the XK120 was quite clearly no slouch, minor- and factory approved - modifications would see the power be able to be increased from 160 to 220hp over the XK120’s six years of production from 1948-1954. The XK120 SE, for special equipment, was first noted in a service bulletin from 1951 and brought the output to 180hp through a combination of higher lift camshafts and dual exhaust pipes. In 1953 Jaguar dealerships began offering to fit the cars with C-Type heads and larger SU H8 carbs, which brought the power to 210hp while the addition of Weber 40mm carbs and manifolds paired with the C-type heads saw 220hp on the dyno. 

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Today, the XK120 turns heads at country clubs and the lawns of various concours, where it still stands out due to its gorgeous curves and regal bearing. In an era where Jaguar happens to be going through a particularly, shall we say “divisive” corporate rebranding, let's never forget that Mr. Lyons didn’t just bring us some of the most beautiful cars to ever grace the road, in the XK120, he also gave us the original supercar. 

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