The 1948 Jaguar XK120 a car put into production by popular demand

The 1948 Jaguar XK120 a car put into production by popular demand

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Before the XK 120 was introduced, Jaguar had not build a sports car for nearly a decade, when they stopped producing the unfortunately named SS Jaguar 100 in 1939. This car was developed solely to allow the chief engineer at Jaguar to test out an engine they had developed but it garnered so much attention at the London Auto Show, the company decided to put it into production. In 1949 the first of the production run was delivered to Clark Gable. So today I want to talk about this incredible vintage sports car, boil the kettle, sit back and let’s get British.



Although new automobile engine development was prohibited during World War II, the company known as Swallow Sidecar Company (SS) decided that they wanted to produce engines in house for their post war cars. The company had used 2.5 liter and 3 liter six cylinder engines from Standard Motor Company for the SS Jaguar prior to the war but Sir William Lyons and his chief engineer, William Heynes, had discussions in secret about developing an entirely in house power train. The rumours over the years are that the company developed prototypes in secret.

In the years after the way, the company started testing its new engines, mainly a 1.8 litre 4 cylinder but by 1946 the company had a 3.2 litre flat six being tested. Heynes started work on a chassis to test his car which they finally showed off as the XK120 prototype at the 1948 London Motor Show. The car was never intended to be put into production but after the sensation it caused at the show Lyons decided that it should be put into production and 242 were put into production that year.


The car maintained the look of the concept car shown with the exception that the pillars around of the windshield were now curved. The two seat sports car looks glorious and set the precedent for an era of incredible looking British sports cars that would follow.

SS Jaguar 100

The car’s looks were a curved version of the pre-war SS Jaguar 100, a more modern take on that car. By this point the company had changed its name to Jaguar as the SS name now would remind people of the SS Nazi officers from the war. The car retained a lot of the looks of its Jaguar 100 brother with the overall shape and round headlights but the body was curved at the front.

The body was made from aluminum to keep it lightweight and placed on a wooden ash frame, with wood lining the entire interior for a classic British sports car look. A single glance at this car would make you understand why it caused such a sensation at its unveiling. In 1950, all future models were built with pressed steel, which was easier for the company to make and hence eased the cost of production and allowed them to keep up with demand.


The final engine which would go in the production car was an evolution of the 3.2 liter flat six in the concept car, being a 3.4 litre flat six Dual Overhead Camshaft (DOHC) engine. It initially produced 160 bhp but by the end of its production in 1954 the added webber carbs and tuning brought this engine up to a massive (for the time) 220 bhp.


It had a top speed of 124 mph, although at initial testing, Jaguar rated it at 120 mph which is where it gets its XK120 moniker. The car would do a 0-60 mph run in only 10 seconds which was a mind boggling speed for a car in 1948 and put it far ahead of anything of the time. When this car was first sold it was the fastest production car in the world.


The car sold in 1948 for £1263 including taxes, selling 242 units in its first year and going on to sell a total of 12,055 units in its 6 year run. This car put the newly formed Jaguar on the map and brought back its prewar sports car name.

The car is legendary these days and a collectors favourite. Richard Hammond has one and Jay Leno has an even nicer one.