Heralded at the time of its release as the fastest production car in the world, the Jaguar XK120 immediately made headlines. Launched at the London Motor Show in 1948, the XK120 not only laid a good deal of the foundation for the racing success of future Jaguar models to come, it also achieved results in its own right, including the highest-ever finish for a British marque at the Mille Miglia.
The Italian connection didn’t end with the famed 1000-mile race though, as a story of romance and derring do—the likes of which only history can provide—brought together Coventry’s big cat with the dark horse contender for the title of Italy’s greatest road racing driver.
The XK120 was the manufacturer’s first sportscar since the company rebranded as Jaguar in 1945, and the OTS (open two-seater) was also the first to use Jaguar’s legendary XK straight-six engine, designed by the marque’s chief engineer, William Heynes. A 3.4-liter capacity generating 160 horses, the XK was ahead of its time.
A dual overhead camshaft design, distinctive for sporting polished alloy covers, was selected as the preferable arrangement for the wide-angle valve layout, which fed into hemispherical combustion chambers. The cylinder head featured a curved inlet, designed to improve the combustion of the mix, and its aluminum construction resulted in a lightweight package.
The fact that the XK engine remained in production until 1992, albeit in displacements which eventually ranged from 2.4 all the way to 4.2 liters, was no accident; it had been designed from the start to provide a platform that could generate an output which would be able to compete into the future with updates, but without extensive redevelopment. Quite whether William Heynes envisaged that his brainchild would remain in production for quite so long (over 40 years), is another story.
Initially ash-framed below an aluminum body positioned on a steel chassis, 242 vehicles in this configuration were produced, the first of which was delivered to Hollywood’s Clark Gable. Gone with the wind at a top speed of 120mph, it was the fastest production car in the world at that time, and its top speed gave the model the “120” part of its name. Demand was strong soon after release, and, mainly because Jaguar reasoned that it wouldn’t be able to keep up with supply, it was decided that the ash frame would have to be replaced with an all-steel version. This added an extra 110lbs, although aluminum was retained for the bonnet, trunk lid, and doors.
Production cars were fitted with torsion spring suspension incorporated on the front, leaf spring to the rear, with stopping power provided by drum brakes on all four wheels. In addition to the OTS, a solid top fixed-head coupe was added in 1951, and a retractable cover drop head coupe completed the range in 1953.
But already by 1949, the XK120 had achieved nearly 133mph in a flying mile, and secured a race win that same year at a one-hour production car race at Silverstone, with Leslie Johnson—part-time businessman, part-time racing driver—behind the wheel. The following year, the XK120 was the first production car to average over 100mph for 24 hours, with Leslie Johnson sharing the driving this time with a young Stirling Moss. And it was in 1950 that Jaguar allocated six lightweight, alloy-bodied XK120s to five promising British racing drivers of the day—as well as one very significant Italian.
Clemente Biondetti was certainly not afraid to do things his own way. Born in Sardinia but an adopted Tuscan, his pursuit of racing success included episodes such as reputedly combining eight 500cc Norton motorcycle engines with the goal of creating an eight-cylinder engine. Regardless of the veracity of that claim, Clemente Biondetti remains Italy’s most victorious road racer, as well as being the holder of a record four wins at the Mille Miglia.
Despite taking the win in the final pre-war Mille Miglia, by 1947 Biondetti didn’t enjoy the same reputation with the famous Italian car houses he once did; 1938 seemed long ago, especially in the eyes of a country trying to rebuild its glory after the destructive years. So for 1947 and the first post-war running of the race, Biondetti found himself without a car. But with characteristic pluck, he traveled from his home in Florence by train to the start in Brescia in the vain hope of finding a way of competing. Meanwhile, Emilio Romano had prepared his own Alfa Romeo 8C, the same model which Biondetti had secured victory with in 1938. On meeting the former champion in Brescia, Romano confirmed the partnership.
Despite the fairytale of Biondetti and Romano actually winning the race, Tazio Nuvolari, the darling of Italian racing drivers, had led the event until misfortune and a storm hit him late in the race, forcing him to slow until he was overtaken by Biondetti and Romano. Such was the storm that there were virtually no media crews and only a handful of spectators to great and crown the champions at the finish. For this reason, in many ways it was Nuvolari who was remembered as the winner in 1947 despite the reality.
The result however secured Biondetti’s deserved recognition, and he was drawn into Scuderia Ferrari, repaying Enzo with victories in the next two editions of Italy’s most prestigious road race, as well as doing the double with victories in Sicily’s Targa Florio in both ’48 and ’49. But perhaps through his advancing age, perhaps through his approach, the characteristically business-like method of Ferrari’s racing department drew an end to their agreement, which brings us back to 1950 and the story of the XK120.
While Biondetti had an unrivaled record of victories, he was out of favor and without a team. Jaguar meanwhile was on the threshold of motorsport’s world stage. Clemente met Jaguar Motorsport’s Frank “Lofty” England at Geneva’s 1950 motorshow; it was a relationship which surely couldn’t deliver important victories that early on, but both sides had everything to gain, and Jaguar certainly needed an established, experienced driver to see what its cars could really do.
The XK120 registration JWK 650 was driven by a Jaguar mechanic to Lugano, Switzerland, where he was met by Biondetti, and together they made their first tests on the road heading south to Florence. With his characteristic customization, Biondetti made adjustments to the car almost right away, including replacement of body parts with aluminum alloy versions to reduce weight, switching the seat to a bucket-type, as well as replacing the windshield with plexiglass. However, the British car remained right hand drive (although Biondetti switched the position of the speedo and rev counter to suit), and it also retained the spats covering the rear wheels, whereas later variants had removed this design.
Biondetti also kept the bumper, which he and Jaguar agreed would demonstrate the genuine look of the production car to the crowds and media of the day, and positioned just above it was a fog light for vital sight whenever conditions worsened. The car carried the number 729, as well as Italian and British flags to celebrate the partnership of the nations. With his co-driver mechanic, Gino Bronzoni, the pair then headed south to Sicily.
Against expectation, though perhaps not so for Biondetti, they were running extremely high in the field at the Targa Florio, which took place in April 1950 and marked Jaguar’s first big event. Biondetti was in second place only to Scuderia Ferrari’s Alberto Ascari and had a two-minute advantage over third place, as well an encouraging lead over another Ferrari, Vittorio Mariotto’s in third. Connecting rod failure dashed Biondetti’s hopes though, and his XK120 was forced to retire, but the showing up to that point was enough to give confidence for the Mille Miglia the following month.
From Brescia’s starting line, Biondetti made great progress and was high in the field, but suspension problems and a broken spring cost him precious time. His eighth place result was an admirable performance, and Leslie Johnson and John Lea did even better, taking their XK120 to fifth place. This was the best finish for a British manufacturer in the Mille Miglia.
Biondetti was encouraged in the wake of the Targa Florio and Mille Miglia, and while he knew his team would remain as outsiders, he was determined to enter that year’s Italian Grand Prix at Monza in September. Though Grand Prix competition was a stretch too far for the Coventry manufacturer at the time, Jaguar consented to Biondetti taking an XK engine all the same.
Using that engine as a starting point, Biondetti developed his own chassis—though some say he used an existing Maserati frame—and combined it with a lighter body from a Ferrari 166. Biondetti qualified for the Grand Prix, and while his machine was forced to abandon after 15 laps on race day, it was an admirable effort especially against the mightiest brands in the world.
Success did eventually come for the “Biondetti speciale” when he won with his car at the Florence-Fiesole hillclimb the following year, setting the overall course record, which gave him plenty of confidence for the next Mille Miglia. Tremendous disappointment greeted Biondetti however, when after 140km he was forced to withdraw, damaging the chassis to the extent that continuing was beyond question.
In 1952, it was a tough decision for Biondetti between the new Jaguar C-Type and a ride with Ferrari, but he returned to his home brand for his final years, taking victory at the 12 Hours of Pescara at the grand age of 53, as well as fourth at the Mille Miglia in 1954. Suffering from cancer, Biondetti was forced to retire later that year before dying from the disease in 1955 at the age of 56.
The connection between the names Biondetti and Jaguar lives on to this day however, through this XK120, which belongs to Clemente Biondetti’s nephew, Stefano. For this article we have photographed the car in Tuscany, where Clemente once lived.
This 1951 XK120 OTS roadster carries the same JWK650 registration plate, as well as the number 729, and the white painted circle on the front (applied so the crowd could recognize the Biondetti car from a distance), as well Italian and British flags on the sides. Despite other claims, Stefano believes that his uncle’s original Jag was ultimately broken up as a donor for other projects.
Like his uncle, but at a much more leisurely pace, Stefano’s Jaguar has also taken part in many runnings of the Mille Miglia since the 81st edition of the event in 2008. The car was driven in its first Mille Miglia outing by Stefano himself, along with car collector and longtime friend Carlo Steinhauslin. And in subsequent editions of the race, it was driven by Stefano’s sister, Paola Biondetti, and Stefano Varia, and so far they’ve always managed a fine finishing position—it seems Clemente Biondetti passed down more than just an appreciation for the Jaguar XK120.
