Jaguar XK120: modified or original?

By Graeme Hurst

| 29 Jan 2024

Classic & Sports Car – Jaguar XK120: is a modified XK better than the original?

Standard or modified? The debate has taken place at many a classic car club meet between the purists, who advocate originality at all costs, and those who say the factory item can be bettered.

And few marques spark more heated discussion than Jaguar.

When the firmʼs XK120 was launched in 1948, it was a watershed model for the company.

This Nigel Dawes-fettled Jaguar XK120 has several tasteful modifications

William Lyonsʼ irresistible combination of 120mph performance and stylish looks for an unbeatable £998 price wowed a wary post-war public when the XK120 appeared at Earls Court in 1948.

It was such a sensation that the initial run of around 250 alloy-bodied cars quickly gave way to high-volume steel production, which in turn led to the roomier XK140 and bloated – but more accomplished – XK150 models.

Some 30,000 XKs rolled out of Browns Lane before the E-type took over in 1961.

Today, however, as the classic fraternity grows, the reality is that there is an increasing demand for extra performance and comfort – particularly among those who have only ever driven a modern car before.

Recent decades have brought a massive growth in specialists offering a plethora of upgrades to help XK owners get more out of their cars.

Uprated brakes, five-speed ʼboxes and rack-and-pinion steering are typical options, but not all upgrades are tasteful.

It is now possible to buy a Jaguar XK with more wood and leather than a theme pub, plus everything from a modern fuel-injected V8 to anti-lock brakes and all-independent suspension under its too-shiny skin.

One XK enthusiast who set a more discreet standard in the early 1990s was Nigel Dawes.

We find out if you really can improve on Jaguar’s seminal XK series by comparing the ‘Dawes’ XK120 with this standard fhc

Then a collector and dealer in exotic cars, Nigelʼs idea of mechanically and aesthetically upgrading the XK120 coupé to fulfil his own aesthetic desires led to a run of half a dozen examples.

“I only meant to do it for myself,” explains Nigel, “but then friends started asking if I would do one for them, and so on. In the end we did six 120 coupés.”

The beauty of any modification is so often in the eye of the beholder, but the Dawes XKs boast a raft of exquisitely executed comfort and styling refinements that makes them highly sought-after.

So much so that the ʻDawesʼ concept has been emulated by others, with many a modified XK advertised as ʻNigel Dawes specʼ.

Jaguar specialist Classic Motor Cars is a case in point, building six more coupés to the same specification, with Nigelʼs endorsement.

To find out why his formula has enjoyed such enduring appeal and acceptance, Classic & Sports Car united the last of Nigelʼs original XK120s with a delightfully standard example.

The 120 fixed-head is regarded by many enthusiasts as the most beautiful of all XKs.

Its tight roofline enhances the carʼs shape, instead of detracting from it like so many tin-topped versions of open sports cars, while echoing Bugattiʼs elegant Type 57 Atalante in profile.

So when Nigel sought to create the ultimate XK, it was the coupé he went for.

The standard Jaguar XK120 interior is well-appointed, but tall drivers might struggle to squeeze behind the large steering wheel, which protrudes far from the dashboard

KSF 7 was bought at auction but was first owned by Ecurie Ecosse driver Ian Stewart.

“It was his personal car for getting to race meetings,” says Nigel. “In those days there was a waiting list, but Ecurie Ecosse drivers could get XKs from the factory.”

Like each of the Dawes cars, it was given a full body-off rebuild that began with seam-welding the entire chassis to improve its torsional rigidity – a labour-intensive task that the factory could never have contemplated.

The chassis build highlights the first Dawes upgrades: competition torsion bars and front anti-roll bar to reduce body roll and firm up the ride, plus rear anti-tramp bars and adjustable Spax telescopic dampers all round.

A rack-and-pinion conversion sharpened the steering, while the fade-prone drum brakes were ditched in favour of dual-servo discs all round, with four-pot calipers up front.

All of this was to handle the extra power from an enlarged 3.8-litre engine, boasting a big-valve C-type head and fed by a set of sand-cast 2in SU carburettors, mated to an all-synchromesh Jaguar overdrive gearbox for improved gearing.

Making an XK go, corner and stop better is nothing new, but itʼs the artistic touches that set the Dawes cars apart.

A trained silversmith, Nigelʼs vocation is reflected in the brightwork: the door and boot handles, bumper overriders and tail-light plinths are all cast in aluminium to reduce weight.

Jaguar’s standard 3.4-litre XK engine makes 160bhp

Even the bumper irons are aluminium and the windows – apart from the front windscreens – are Perspex.

Under the louvred bonnet there are plenty of race-inspired touches, such as the Le Mans-style oil-filler cap, twin coils, aluminium radiator and oil breather catch tank, plus a holder for a spare set of spark plugs.

The airbox has a ram tube from a special grille vent – just like the Le Mans XKs – and tweaks to the front valance vents feed air to the brakes.

A recessed Le Mans fuel filler finishes off the look, along with a mesh grille in place of the fluted original.

But itʼs inside that Nigelʼs eye for detail and perfectionist streak has had the biggest impact, with dozens of enhancements to the already plush ambience.

There are more gauges for a start, including separate oil pressure and temperature clocks ahead of the driver and a D-type speedo and telltale rev counter.

A new centre console houses stopwatch and Halda SpeedPilot, while a separate map light and blue dash lights add to the rally feel.

Thereʼs also a recessed fuel tap on the floor, plus a drilled battery cut-out switch behind the seats.

The Dawes Jaguar XK120 boasts a two-drawer toolkit in the boot, plus the signatures of Ecurie Ecosse driver Ian Stewart and former Jaguar test driver Norman Dewis

Parked beside Chris Jaquesʼ fabulously period Birch Grey 1953 standard example, with its stylish spatted steel wheels, the Dawes car looks a little over-egged in places.

Nevertheless, you canʼt help admiring how well it has been executed.

The leather is all double-stitched, even across the top of the dashboard, which is something Lyonsʼ built-to-a-price philosophy couldnʼt possibly have absorbed.

There are other surprising touches, such as a special recess behind the seats to stow your maps and a time delay for the courtesy light so you arenʼt left fumbling for your keys in the dark.

Finishing it all off is a set of 5½in (½in wider than standard) Borrani wire wheels whose lighter, part-aluminium construction reduces unsprung weight.

The metallic paint is in the same hue as the Aston Martin Project 215 car, which Nigel once owned.

He also went a step further than Lyons by creating a crease line where the bonnet blends into the wing, instead of the original tight curve.

The Dawes Jaguar XK120’s modified interior has D-type dials and a wood-rimmed steering wheel that sits closer to the dashboard

For me itʼs a step too far for such a historic car because it borders on customising, but it came about as a result of Nigelʼs critical eye.

“Lyons was a brilliant stylist,” he says, “but I wanted to improve the design by highlighting the XK120ʼs lines.”

None of the Dawes XKs were officially road tested in period to quantify any performance gains, but a stint in the standard car gives a benchmark for the difference in character.

And just getting in gives the first clue to why so many early XKs are modified: anyone over 5ft 6in tall is going to struggle to fit.

Fortunately, this example has period bucket seats so thereʼs a touch more room, but itʼs still a squeeze – particularly with the steering wheel sticking so far out of the dashboard.

The engine fires with that distinctive twin-cam growl, but in small-valve 160bhp configuration itʼs incredibly sweet.

Pull away and you get another traditional Jaguar experience with the slow-changing Moss gearbox.

The Dawes Jaguar XK120 has a Le Mans-style fuel cap (left); the fuel tap in the Jaguar’s floor

It doesnʼt suffer fools but rewards precision, as does the heavy Burman steering, which needs subtle and constant inputs to keep your chosen line.

On more modern radial tyres, this car doesnʼt exhibit the classic crossply tramlining, but the ride is still on the soft side and thereʼs a fair bit of body roll when you tackle a corner at speed.

The unservoed all-round drums also add to the heavy feel of the controls, but they give a reassuring bite if you stomp on them.

Itʼs in keeping with this standard carʼs harmonious character and the perception that each and every component is designed to do its job competently with repeated use.

Step into the Dawes XK and youʼre struck by how much extra room there is, thanks to alterations to the rear bulkhead that allow the seat to go back a much-needed few additional inches.

Together with a shorter steering column (a bonus of the switch to a rack-and-pinion set-up), it means six-footers can get comfortable and the wide, drilled alloy pedals are more reassuring than the dainty originals.

The all-synchro ʼbox feels sturdier, too: just as well, because thereʼs no disputing the extra urge.

An enlarged 3.8-litre block, a big-valve C-type head and a set of sand-cast 2in SU carburettors give around 230bhp in the Nigel Dawes Jaguar XK120

As the deliciously cammy ʻsixʼ comes on song, you revel in the wide spread of torque.

It sounds racy, too, with the soft growl evolving into more of a muted bellow as the D-type-spec camshafts do their bit at higher revs.

But itʼs the road manners that really impress: the firmer suspension and sharper steering mean less roll and more precision, especially if the car is suddenly unsettled in a corner.

The servo brakes are hugely powerful, with a more progressive action than the factory carʼs drums.

It inspires massive confidence: you get the sense it will go as fast as you dare drive it.

Whether or not CMC follows Nigelʼs lead in the styling enhancements, it unsurprisingly plans to incorporate all the other bits.

“Itʼs the detail on the Dawes cars that really sets them apart,” explains CMCʼs Nick Goldthorp, who will use the firmʼs engineering expertise to further improve the XKʼs suspension geometry.

CMC will also include a limited-slip differential and power-assisted steering, while modern air conditioning will be optional.

Images: Tony Baker

Thanks to: Nigel Dawes, Chris Jaques and CMC

This was first in our October 2008 magazine; all information was correct at the date of original publication

Factfile

Jaguar XK120 fhc
[figures for Dawes XK120 where different]

Sold/number built 1951-’54/2672 [1988-’96/six]
Construction steel body, steel ladder chassis
Engine iron-block, alloy-head, dohc 3442cc straight-six, with twin 1¾in SU carburettors [3781cc with C-type head, 2in sand-cast SUs]
Max power 160bhp @ 5200rpm [230bhp (est)]
Max torque 195lb ft @ 2500rpm [n/a]
Transmission four-speed manual, RWD [all-synchromesh four-speed with overdrive]
Suspension: front independent, by wishbones, torsion bars, telescopic dampers, anti-roll bar [competition torsion bars, gas-filled dampers] rear live axle, semi-elliptic leaf springs, lever-arm dampers [anti-tramp bars, gas-filled telescopic dampers]
Steering Burman recirculating ball [rack and pinion]
Brakes drums [discs, with servo]
Length 14ft 5½in (4407mm)
Width 5ft 2in (1574mm)
Height 4ft 5½in (1360mm)
Wheelbase 8ft 6in (2590mm)
Weight 2856lb (1295kg)
Mpg 19 [n/a]
0-60mph 12 secs [n/a]
Top speed 120mph [130mph (est)]
Price new £1694 [£60,000]