September 10, 1975 was announced as a black day for Modena, Stuttgart and Turin by Jaguar’s marketing department.

That was the day that the company unveiled the new XJ-S, the long-awaited replacement for the glorious E-Type which had finished production the previous year. The long lines and V12 in the nose might have continued, but the difference in design ethos was obvious: ’60s curves gave way to ’70s straight edges and performance was definitely modern as well. Sub seven seconds was quoted for the sprint to 60mph and 150mph as the top speed, up there with far more expensive Italian output from the suburbs around Modena.

But if the looks were good, the timing wasn’t. The mid ’70s in Europe wasn’t the time for a petrol-guzzling sportscar in the mass market, and Jaguar’s motorsport activities were under tight control. In fact, the company’s board had little interest in racing their new charge, so it needed a covert approach to an American race team by a senior manager for a chance to see the new Big Cat on track.

Across the Atlantic was a market where the fuel efficiency or otherwise of the big GT was less of an issue, so not for the first time Bob Tullius’ Group44 squad would be the team chosen to campaign British cars in the USA. Tullius was a veteran driver and team owner, with a fine history importing and racing the British Leyland group’s cars going back to the previous decade. He’d previously developed and driven Triumphs and MGs with British factory support to multiple victories in SCCA club races.

Group44 had already produced a racing version of a late model E-Type in the mid ’70s – a brutal, stripped-down take on the roadster – and they would go on to kickstart Jaguar’s assault on Group C during the ’80s. If not for yet another intervention by the American team, it’s unlikely there would have been all that 1980s Group C success for Jaguar… But in between, Tullius’ team took on the new XJ-S, developing it for SCCA Trans-Am competition.

At first glance the car looked relatively stock, a trick of the car’s long length misleading the eye when it came to width.

But the XJ-S’s fenders were seriously widened.

Huge racing rubber was bolted on to these glorious split rims.

Group44’s iconic livery was already well established with their previous cars, and the white with green stripes came to define racing Jaguars until the classic Silk Cut liveries of the mid ’80s – and as ever it was Tullius himself who pedalled the car in the US.

Looking inside cars like this reminds you of just how simple and stripped back old racing cars are. Group44 tore the interior down – and with such a big space to sit in the driver must have felt like they were driving a supertanker…

Especially when the driver was dropped into this diminutive slip of a seat, with no head support. It’s quite a contrast to the all-enclosing nature of modern seats. An eight-point rollcage was fitted inside the stripped-out shell, which went a long way in improving stiffness.

The XJ-S was definitely a car that required brawn to master.

Though, if the security of the driving position might have been an issue, understanding the simple switchegear definitely wouldn’t be.

The small racing wheel, complete with another reminder of the motivation in front of you (there are plenty dotted over the car), connected via a standard Jaguar power steering unit to the front axle.

Group44 built the car in 1976, also racing it four times towards the end of the season to speed up development ahead of a full campaign the following year.

The racecar for ’77 was based on a left-hooker production XJ-S chassis, then for ’78 a silhouette tube-frame car was developed, with weight was dramatically cut away, which raced alongside this car and allowed Group44 to deliver both the manufacturers as well as drivers cup on behalf of Jaguar.

Nothing really survived of the donor car though: just the roof panel and a couple of components here and there.

Group44’s XJ-S was on the pace straight away, and Tullius swept to the driver’s championship in ’77. He won five times and got on the podium a further two times in his singleton XJ-S against the massed Monzas, Porsches and Corvettes.

This car originally came from Bob Tullius’ own collection, and had been fully restored back in 1991. Now housed at classic racing specialists JD Classics, the engine and transmission was out for a rebuild during my visit, leaving an impressively large hole in the cockpit.

There was an even bigger one under the bonnet. With the big engine out, it really gives a sense of the size of the nose. For comedy effect I like to imagine what a little Gordini straight four would look like in there…

The Jag’s 5.5-litre V12 was sitting in the race workshop, awaiting allocation of time in the ever-busy engine department at JD Classics, but being out of the car meant getting a better idea of the enormous length of the thing.

Power was not something the Group44 XJ-S was short of. The car might have been based on a production chassis, but the V12 pumped out somewhere around 540hp by the end of its competitive life thanks to the work of Group44, up from an original figure of 475hp.

Power was delivered through a four-speed ‘box straight from the road car, which would normally be situated just about here…

The XJ-S was converted to a bespoke dry sump oil system, and the street Lucas/Bosch D-Jetronic fuel injection system stripped out and replaced with six twin-choke Weber 441DF carburettors.

The suspension was tweaked and AP Racing brakes fitted, but the general layout and handling of the base car certainly helped development – another tick for Malcolm Sayers.

Straight pipes with no mufflers gave the car a surprisingly grunty sound. Here’s the ’78 car ticking over. Simply awesome.

The big boot was used for the fuel system – in Trans-Am races there wasn’t a need for quick refuelling.

The hole in the bonnet for the jacks was the only bit that looked crude across the whole car.

As you can see in this video, the car looks surprisingly stable for such a big, long car – and generally very solid riding over bumpy US tracks. Check about seven minutes into this clip from the ’70s, where it’s even described as being ‘suspiciously smooth.’ And then 19 minutes in for some awesome footage from Laguna Seca.

Over powered and over there, the Group44 was yet another British wolf in sheep’s clothing from the US powerhouse team. Now I just need to track down Group44’s Triumph TR8 that followed this car…

Jonathan Moore
Instagram: speedhunters_jonathan
jonathan@speedhunters.com