Mercedes-Benz 300SEL 6.3 vs Jensen FF: inconspicuous consumption

By Martin Buckley

| 9 Sep 2022

Classic & Sports Car - Mercedes-Benz 300SEL 6.3 vs Jensen FF: inconspicuous consumption

One is a formal, elegant four-door German saloon with that giant engine: the original ‘banker’s hot rod’, indistinguishable from half a dozen of its more pedestrian siblings in all but those magic numbers on the right-hand side of its bootlid.

The other car is a svelte, boutique grand tourer: American-powered and Italian-styled, but from a bravely innovative British specialist manufacturer.

Only the double wing vents – and a stainless-steel roof – hint at its high-tech status as the world’s first four-wheel-drive high-performance road car.

Both the Jensen FF and the Mercedes-Benz 300SEL 6.3 were early adopters of safety as a selling point

But do the Jensen FF and Mercedes-Benz 300SEL 6.3 really compare?

They would have appealed to similar people: buyers more sensitive to image than cost, who had grown out of sports cars but were still keen on driving; who didn’t want another Jaguar and considered themselves too young for a Rolls-Royce.

At £7273 for the import-duty-inflated Mercedes and £6857 for the Jensen, these cars were pitched into the Silver Shadow class and represented about the most you could pay for an owner/driver vehicle with four seats and high-performance overtones that was also a practical means of transportation.

The Mercedes’ cabin feels cavernous after spending some time with the Jensen

Unlike certain Italian exotics that were making overtures at the four-seater market, the 6.3 and FF were neither toys nor fashion statements, but working vehicles designed to ease motoring anxieties and massage wealthy egos.

For the purposes of this essay, let’s ignore the disparity in the size of the rear seats and the number of doors: they were probably less of a deal-breaker than you might imagine in period.

In daily use the rear cabins of these cars were rarely occupied, which was just as well for the Jensen because it was only a true long-distance four-seater by negotiation with the occupants of its front chairs: the FF’s rear-seat legroom was as intimate as the Mercedes’ was lavish, but, once installed, it was comfortable enough.

The classic Mercedes-Benz 300SEL 6.3’s staid styling belies the urge of its V8

In fairness Jensen called its flagship a ‘close-coupled saloon’, with sufficient room to retain at least the illusion of respectability in the executive car park.

Both our protagonists are automatics, and you would not want them any other way.

Weighing in at around 3800-4000lb (the British car is the heavier), both have the legs to top 130mph – if we assume the Jensen’s Chrysler V8 produces about the same installed ‘net’ 250bhp as the Benz – with similar rear-axle ratios.

Rear legroom is generous in the Mercedes-Benz 300SEL 6.3

They get to 100mph in about the same time the average 1969 family saloon could hit 60mph. And all this with a commensurate thirst for high-octane fuel: maybe 15mpg on a run in the Merc, dipping into single figures around town in the Jensen.

At six shillings and sixpence a gallon (or an inflation-adjusted £4), anyone who could afford a £7000 super-tourer at the end of the 1960s probably didn’t worry about petrol bills.

They might, however, have been disappointed by the inconvenience of a sub-200-mile range from the Jensen’s 16-gallon fuel tank.

But beyond these observations, other parallels – technical or otherwise – become harder to find.

The well-specced Mercedes boasts air conditioning

Both cars are steel-bodied, but where the mechanically fuel-injected, air-bag-suspended Mercedes is based on a mass-produced (if hand-finished) monocoque bodyshell, the Jensen’s Touring-styled, Vignale-crafted panels are welded, artisan-style, to a tubular chassis.

The result is a handbuilt mongrel of American power and refinement, svelte Italian styling and Black Country ingenuity: the product of a small company – and a few key individuals – that wanted to build a luxury GT which was not only fast, but also inherently safe.

Having pioneered disc brakes and standard-issue seatbelts on British vehicles, brothers Alan and Richard Jensen had a fine record in that department.

Mercedes-Benz embraced energy-absorbing crumple zones for the 109-series

Big Mercedes saloons were already safe thanks to their crumple zones, but they weren’t conspicuously fast.

The 300SEL 6.3 was born out of one Stuttgart engineer’s frustration at the firm’s stodgy mid-’60s reputation for building cars for ‘old men’.

It was only by happy chance that the M100 V8 – from the slow-selling 600 limousine – happened to fit in the W109 saloon body.

Erich Waxenberger’s Teutonic muscle car is both a legend and a true oddity in the smooth, carefully calculated progression of Mercedes history.

‘Our protagonists get to 100mph in about the same time the average 1969 saloon could hit 60mph, with a commensurate thirst for high-octane fuel’

Daimler-Benz built 6526 of them between 1968 and 1972; its success – particularly in North America – took the company by surprise, coming late in the model cycle of the S Class W108/W109 shape that had first been seen in 1965.

Road & Track helped shore up the 6.3 myth by subtitling its November 1968 road test ‘Merely the Greatest Sedan in the World’.

In the UK, 6.3 customers included George Harrison, Mick Jagger and a whole slew of Formula One drivers who all enjoyed the subterfuge of such urgent power in so conservative a body.

Under the classic Mercedes 6.3’s vast bonnet sits the mighty M100 V8

The FF, in contrast, made an impact out of all proportion to the 320 built between 1967 and its untimely 1971 demise.

It was a prodigy of a car that, 13 years before the Audi quattro, should have changed the motoring landscape.

Ferguson Formula four-wheel drive and Dunlop anti-lock technology were truly sensational developments in the mid-’60s, although the Maxaret braking system – developed in the aerospace industry – never quite won over the critics.

Although down on power, the 300SEL’s 6.3-litre V8 (front) propels the Mercedes to 120mph three seconds faster than the Jensen FF

Only 25 FFs had been produced by the end of 1967 and when, by 1971, it became obvious that the low-volume sales made a Federal crash test programme commercially unjustifiable, its fate was sealed.

The irony that ‘the safest car in the world’ had been killed off by American safety legislation wasn’t lost on the FF’s fans.

Between 1966 and ’69 195 Mk1s – such as this one – were built, followed by 110 MkIIs and just 15 MkIIIs.

Around 700 right-hand-drive SEL 6.3s were made, but not all for the UK.

The Mercedes’ air springs give a supple ride and keep things neatly under control on the brakes

This blue 1970 car – for sale at SL Shop – has recently had a course of improvements aimed at its notoriously costly suspension, and it drives better than any other I have tried.

Likewise, Martin Ritchie’s 1969 Jensen FF, bought from the family of its original owner 15 years ago, is a superbly maintained former concours contender.

You ‘wear’ the low-slung Jensen but feel almost lonely in the Mercedes, with all that space behind.

Both cars are plush, but you don’t realise how luxurious the 300SEL is in the hierarchy of Mercedes-Benz saloons until you contrast it with the MB-Tex wasteland of a 280SE 3.5.

The four-wheel-drive Jensen FF (left) feels planted, whilst the nose-heavy Mercedes-Benz 300SEL 6.3 can’t help but roll when pushed in corners

All-round vision in both cars is in the goldfish-bowl class compared with any modern.

Particularly commanding are the views across the bonnet of the 300SEL, with its giant steering wheel, sensibly laid-out dash – complete with tiny rev counter – and clap-hands wipers. The lever by your right knee is the height adjustment for the 6.3’s air suspension.

There is something almost Miura-like about the FF’s highly styled dream-car flight deck, with its plethora of ‘Guinness bottle’ flick-switches and Jensen-branded 8-Track player.

The black knob low on the central stack is for the Selectaride rear dampers, dropped on later FFs.

The Mercedes-Benz 6.3’s V8 sounds hard and metallic compared to the Jensen FF’s commanding burble

Both cars have electric windows, but only the Mercedes has air conditioning, and passengers in the FF have a skinnier front seat due to the ingress of the transfer box.

Under the 300SEL’s bonnet there is something quasi-military about the presentation of the M100 V8.

With massive injection trunking, it fills the space like an escapee from the engine room of a Second World War torpedo boat.

The little pump at the front is for the air suspension, one of the glories – but also one of the key failings – of this mighty vehicle.

The Jensen FF’s steering is a touch light, but four-wheel drive lends the car a sure-footedness that the sometimes tail-happy Mercedes can’t match

The Jensen’s Chrysler engine, mounted much further back in a chassis slightly longer than the Interceptor’s, is mostly hidden under the big air-cleaner box of its Carter four-barrel carb.

But for its chrome tappet covers, it could easily have come from a delivery van.

Yet, if anything, it is more refined than the Mercedes engine with a much smoother idle.

It goes into ‘D’ gently and urges the car forward with creamy gearchanges and urgent – but not vicious – acceleration, clawing away from rest bereft of wheelspin or drama.

The Jensen’s twin wing vents are one of few ways to differentiate the FF from an Interceptor

Up to 120mph the Jensen, as tested when new, was 3 secs adrift of the Mercedes and feels it subjectively.

Some of this is explained by its additional weight, the drag of the four-wheel drive and the sense that German horses are, perhaps, fitter, leaner and more honest than American ones.

Those horses also sound different: the 6.3 winds out with a hard metallic snarl to the FF’s lusty, authoritative burble.

The gearbox in the Merc is set up to pull away in second – probably to protect the drivetrain components – but you can get first by pushing past the resistance at the end of the throttle travel, resulting in plumes of expensive smoke from the Michelin XWXs and slow, attention-grabbing progress until you ease up.

Driving the Jensen FF allows you to relish the low-slung driving position

The M100’s rev limit is modest – 5100rpm – but Bosch mechanical injection dumps fuel in such generous measures that the throttle response at tickover cannot be anything other than satisfyingly sharp.

Even now there is something epic and instant about the way this Mercedes gathers speed with that thrusting, visceral top-to-third kickdown.

With enough torque to easily break the rear wheels loose on tight corners – even in the dry – this thundering brute of a car appeals to the hooligan in everybody.

The Jensen’s stylish ‘Guinness bottle’ switches and Selectaride rear damper control

With four speeds to the Jensen’s three – and a pure fluid coupling rather than a torque converter – the Mercedes’ gearchanges are not so much jerky as positive, with the delicate little selector lever very much there to be used for extra braking control in third as the big saloon gobbles up another straight.

I surprised myself by preferring the steering of the Mercedes, which had more feel than the Jensen’s powered rack.

Aimed at a fast-approaching curve, the 6.3 rolls quite a lot and feels nose-heavy, but the self-levelling of the air bags curbs front-end dive effectively and the car is well-behaved and balanced on the brakes, with the air springs giving a level of supple refinement that the Jensen’s coils and semi-elliptic leaves do not even pretend to match.

The Jensen FF’s Chrysler-sourced V8 engine packs 425Ib ft of torque

Not that the Jensen rides poorly: the generous sidewalls of its tall tyres and the damping effect of its sheer mass see to that.

But what the FF lacks in ultimate refinement compared with the Mercedes, it tends to regain in the tidy, viceless handling that comes with the higher cornering abilities and superior traction afforded by its vaunted Ferguson four-wheel-drive system.

Turn in, floor the throttle and the back of the FF simply follows the line of the front with grip to spare. It’s a boon to fast, stable A-to-B progress once you are attuned to the over-light but accurate steering.

Marketed as a ‘close-coupled saloon’, rear space in the Jensen FF is limited

It was a revelation in 1967 and remains impressive, even if fast-improving tyre and suspension technology had already begun, by the time of the FF’s demise, to cause some critics to question the need for such complication in a road car whose capabilities most buyers didn’t have the skill to exploit.

The disparity in looks, image and number of doors doesn’t really matter here.

It seems that the Jensen FF and Mercedes-Benz 300SEL 6.3, while products of two very different engineering philosophies, were tasked with remarkably similar missions in life: to provide the fastest, safest and most luxurious land travel possible for four adults, virtually irrespective of price.

The Jensen’s superior traction out of corners is afforded by the Ferguson four-wheel-drive

For me they are two of the truly great cars of the 1960s and early ’70s.

That I’m not alone in this assertion is reflected in the prices asked – six figures are common – and the paucity of cheap, tatty examples of either machine.

Yes, Mercedes 6.3s were cheap, once. Around 25 years ago I could have bought a not-so-scruffy 300SEL 6.3 for two grand but walked away.

Then, as now, it is a brave soul who takes on either car as a project – a person has to know their limitations – but if I had the money to buy a ‘proper’ example of either car, I think I would find the more dashing, more significant and much rarer Jensen FF hardest to resist.

Images: Luc Lacey

Thanks to: SL Shop; Paul Lewis, Jensen Owners’ Club

Factfiles

Mercedes-Benz 300SEL 6.3

Sold/number built 1968-’72/6526
Construction steel monocoque
Engine iron-block, alloy-head, sohc-per-bank 6332cc V8, Bosch mechanical fuel injection
Max power 250bhp @ 4000rpm
Max torque 369Ib ft @ 2800rpm
Transmission four-speed automatic, RWD
Suspension independent, at front by double wishbones rear low-pivot swing-axles; telescopic dampers, air springs, anti-roll bar f/r
Steering power-assisted recirculating ball
Brakes discs, with servo
Length 16ft 8in (5080mm)
Width 5ft 11¼in (1808mm)
Height 4ft 7½in (1408mm)
Wheelbase 9ft 4in (2845mm)
Weight 3800Ib (1724kg)
0-60mph 7.1 secs
Top speed 134mph
Mpg 15
Price new £7743
Price now £80-100,000*

Jensen FF

Sold/number built 1967-’71/320
Construction tubular steel chassis, steel body
Engine all-iron, ohv 6276cc V8, Carter four-barrel carburettor
Max power 325bhp @ 4600rpm
Max torque 425Ib ft @ 2800rpm
Transmission three-speed automatic, 4WD
Suspension: front independent, by double wishbones, twin coil/damper units, anti-roll bar rear live axle, semi-elliptic leaf springs, telescopic dampers, Panhard rod
Steering power-assisted rack and pinion
Brakes discs, with Dunlop Maxaret anti-lock
Length 15ft 11in (4851mm)
Width 5ft 10in (1778mm)
Height 4ft 5in (1346mm)
Wheelbase 9ft 1in (2769mm)
Weight 4012Ib (1820kg)
0-60mph 7.7 secs
Top speed 131mph
Mpg 11-14
Price new £6000
Price now £100,000+*