Start with what the Jaguar Mark X is: a 4-door saloon with 3781 cc XK I6, built from 1961 to 1970, in the decade that gave the world the pony car and the mid-engined supercar. What it meant takes a little longer.
The background
The Jaguar Mark X (Mark Ten), later renamed the Jaguar 420G, is a large, luxury saloon car manufactured by British automaker Jaguar Cars between 1961 and 1970. It succeeded the Mark IX as the top of its range, but broke radically with its predecessors in both styling and technology. From an industrial design viewpoint, the ponton-shaped Mark Ten was a hallmark car for Jaguar by introducing the upright, often slightly forward leaning front fascia and grille, flanked by prominent quad round headlights. When Jaguar replaced its entire saloon range with a more compact single new model in the late 1960s, the resulting XJ6 of 1968 used the Mark Ten as a template.
Similar front grille and quad round headlight facias defined most of Jaguar's saloons for nearly half a century, until 2009 – the final year of both the 3rd generation XJ series, and of the Jaguar X-Type. Also, Jaguar did not build another car as large as the Mark Ten & 420G for the rest of the century, until the LWB version of the 2003 XJ Jaguars. Introduced within a year of Jaguar's E-Type sportscar, the Mark X copied much of the E-Type's technology and specifications. In contrast to its predecessors, the car employed modern styling and technology, with integrated unitary bodywork (the largest in the UK at the time) , four-wheel disc brakes, and Jaguar's independent rear suspension with inboard brakes, unprecedented for early 1960s British luxury cars. Combined with the 3.8-litre, triple carburetor engine as fitted to the E-type, it gave the Jaguar Mark X the capability of handling a top speed of 120 mph (193 km/h) at
The engineering
The engine is 3781 cc XK I6; other versions carried different engines, listed in the specification table below. On the scales it comes to 4200 lb. Drive goes through a 3-speed automatic gearbox / 4-speed manual box with overdrive. The layout matters: a front engine drives the rear wheels, the classic proportion — long bonnet, cabin set back — that most people picture when they picture a sports saloon or a grand tourer. The wheelbase is 120 in. These are manufacturer figures carried by Wikipedia and Wikidata, not road-test measurements.
Where it sits
In the Jaguar line-up the Jaguar Mark X has a clear place: it replaced the Jaguar Mark IX; it handed the line to the Jaguar XJ6 (smaller); the factory was Coventry, England, United Kingdom. The cars a buyer would have weighed it against include the Volvo P1800, the Alfa Romeo Giulia, the Ferrari 250 GTO. Its Jaguar stablemates include the F-Type and the Vanden Plas.
Owning one today
There is no federal ownership record for the Jaguar Mark X — it predates the complaint database or was never sold in the United States — so MotorJury publishes no running-cost figure for it. For a car of this age the price is set by the collector market and the condition of the individual example, not by a formula.