Let’s take a look at Jaguar next.

First the name:
When William Lyons started in business making motorcycle sidecars he called his “Swallow Sidecars”. Once he moved into car body and later car manufacture, the name became SS which variously stood for “Swallow Sports”, “Standard Swallow”, or “Standard Special” (the latter two names be4ing used for cars with Standard chassis and engine or later Standard-based engines. Then the car became the SS Jaguar, the animal name creating an image of piower and speed. After World War 2 with the unpleasant connotations of the initials SS the cars and company became simply “Jaguar”. And it’s been Jaguar ever since.

Next the cars:
Here there are several interlinking threads covering sports cars, saloons and sports racers which I’ll try and unravel, with the emphasis on those that raced or rallied.
The first (prewar) SS cars were the SS I and SS II sports, or rather, GT cars. The next model was the SS 90 so named because it could do 90mph followed by the SS 100. The saloons were simply called the 1˝ litre, 2˝ litre and 3˝ litre SS or SS Jaguar models.

Then came the World War and the well-known story of how William Lyons, and his engineers Bill Heynes, Claude Baily and Wally Hassan conceived and designed a new engine to power the large saloon cars whilst on fire watching duty. They started with the XA and after various prototypes came up with the 6-cylinder 3.4 litre twin overhead cam XK engine.

Poswar, Jaguar initially continued with the prewar cars but named them "Jaguars" and dropping the "SS" with its Nazi connotations.

The first new saloon model postwar was the Mark V. There were no Mks 1 to 4. The Mark V name is reputed to have come about as it was the 5th prototype that was adopted.

The new saloon designed to use the new XK engine was not ready and as a stopgap measure Jaguar installed the engine in a cut down Mk V chassis fitted with a stunning body which was the star of the 1948 motor show – the XK120, named following the prewar tradition as they claimed it would do 120mph. They also announced a similar downmarket model with a 4-cylinder 2-litre engine named the XK100. But the XK120 was such a resounding success that the XK100 was quietly dropped.

The new saloon with the XK engine was finally announced in 1950. Logically it should have been the Mark VI but the current Bentley model was the Continental Mark VI so Jaguar were persuaded to name their new model the Mark VII. Amongst other successes, the Mk VII won the 1957 Monte Carlo Rally. In time the Mk VII became the Mk VIII, Mk IX and ultimately the Mk X and the engine grew to 3.8 litres and later 4.2 litres.

The XK120 was fast and gave a good account of itself. As a rally car it netted Ian Appleyard a Gold Coupe des Alpes in the Alpine Rally for consecutive penalty free runs in 1950-52. But in racing it wasn’t competitive with the Continental racing-derived Ferraris, Delages, Talbots etc. So Jaguar developed a special competition, or sports racing, model with a stiffer tubular frame and lightweight body – the XK120C (for Competition) with chassis numbers XKC 001, to XKC 053 and won Le Mans in 1951 and 1953 with it. It was generally referred to as the “C-Type”.

Then in 1954 they produced a new sports racing car with monocoque construction and even more streamlined lines. Technically this was the Mk 2 Competition model so Jaguar numbered the chassis in the XKC series but started the sequence at XKC 401. But the press and everyone called the new car the “D-Type”. Jaguar bowed to popular demand, adopted the name, and started to number the chassis as XKD~. The 1954 cars being numbered in the XKD 405 and XKD406, the 1955 cars XKD 501 etc and the 1956 cars XKD601 etc. Jaguar withdrew from competition on a high note having scored three consecutive Le Mans wins from 1955 to 1957. But the competition department continued in a low key way. On the competition front, Jaguar produced the E1 prototype that never raced in about 1958 and then in 1960 the prototype E2A (A for aluminium) with independent rear suspension appeared at Le Mans but as a Cunningham entry and not as a works car. Technically this was probably the XKC Mk 3 but was always referred to as the “E-Type”

In 1955 Jaguar introduced a new small 2.4 litre saloon to complement the Mk VII. They simply called it the 2.4 litre and when they introduced a larger engined version it was the 3.4 litre. When Mk 2 versions in 2.4, 3.4 and 3.8 litre form were introduced the early cars were retrospectively named Mk 1’s.

By now the road going sports cars had become the XK140 and later the XK150 - although Jaguar no longer claimed that they could attain those speeds.

In 1961 the E-Type road going sports car was introduced superseding the XK150. Hence E2A had to be retrospectively re-christened the “E Type prototype”. The E-Type’s parentage from the racing D-Type with the IRS of E2A was obvious. (For some reason it was known in the States as the XKE). Jaguar developed the “Lightweight” and “Low drag” E-Types to compete in GT racing against the Ferrari 250 GTO and the Aston Martin DB4GT. But the XK engine was by now outdated as an out-and-out competition engine and the car met with only limited success.

On the saloon car front, things get complicated with engine options being dropped and reinstated and models renamed. The small model became the 240 or 340, but there was no 380 as the 3.8 litre engine was dropped. By now the big model had reached Mark X. The small saloon was given a tail similar to the Markk X, independent rear suspension like the E-Type and a choice of 3.4 and 3.8 litre engines and renamed the S-Type. With the advent of the 4.2 litre engine, the small bodied car was given a nose like the Markk X and became the 420 and the Mark X became the 420G.

Both ranges were replaced by the new XJ6 which combined the two saloons into one model with a range of engines, initially 4.2 and 2.8 litre XK engines. I don’t know the origin of the XJ6 name – one theory is it was the factory code name which the marketing people adopted. The ‘6’ might mean 6-cylinder as when the V12 engine was fitted in the XJ6 body the car was called the XJ12. This was raced but was not successful as Jaguar were not prepared to spend the money on homologated modifications.

Although they had officially withdrawn from racing, Jaguar produced the experimental XJ13 with a prototype V12 engine in the rear in the mid sixties. The reason for the name is a mystery as it was well before the XJ6 and XJ12. But while this was being tested and developed in a low key way, the Ford GT40 and the 7 litre Mk II arrived and the regulations changed so development was stopped before the XJ13 reached the tracks.

The replacement for the E-Type was a fixed head coupé that was more of a GT than a sports car based to a large extent on the XJ6 platform. Possibly to connect it in people’s minds, Jaguar named it the XJS. The XJS body dimensions [just] qualified it as a saloon car and Tom Walkinshaw developed it to win the European Touring Car Championship.

In the USA, Group 44 headed by Bob Tullius raced the V12 E type in SCCA racing netting numerous wins and one national championship and when the XJS arrived they raced it in the Trans Am series with considerable success.

The Group 44 and Tom Walkinshaw operations jointly developed the XJR (XJ Racing?) series of mid engined sports racing cars from the XJR 5 through to the XJR 17. I’ll not go into the various cars and the results achieved as the information is readily available. In summary: they won Le Mans twice, the Team and Driver World Endurance Racing Championships twice each and many IMSA races.

Any takers for tackling the numbering of Porsches or Ferraris?