Completing the specifications for this Bentley 4½ Litre Blower (Chassis No. SM3917) review was the simplest of tasks. I simply referred to a framed line drawing I have had on my wall since I was 10 years old.

WO Bentley might not have agreed with supercharging his 4½-litre model, but the result is surely the quintessence of Bentley lore that every schoolboy should know. Sir Henry “Tim” Birkin and his Blower Bentley are one of the most gallant man and machine partnerships, up there with Horatio Nelson and the Victory, Guy Gibson and his Dambusters Lancaster and Andy Green and Thrust SSC.

In the 1930 Le Mans 24 Hours race, Birkin, dubbed “the greatest Briton of his time” by none other than WO himself, took on the mighty works Mercedes-Benz SSK and its lead driver Rudolf Caracciola. How he overtook the German ace at the end of the Mulsanne straight, on the grass at 125mph, throwing a tyre tread, but contemptuously keeping his foot in, is the stuff of legend. He didn’t finish the race and it’s arguable whether he actually made a difference (works Bentley Speed Sixes came first and second), but this is a fable impervious to mere details.

Birkin had to go behind WO’s back to get the approval to build 50 road Blowers (built between 1927 and 1931) and five additional race cars. Woolf Barnato, Bentley’s chairman and majority shareholder, agreed and Birkin corralled the wherewithal from wealthy racehorse owner Dorothy Paget. Amherst Villiers designed the supercharger and the standard 4½-litre cars were converted in a workshop in Welwyn.

When Birkin beat almost the entire field of Bugatti GP cars at the French Grand Prix at Pau later in 1930 (he came second in what’s generally acknowledged to be his finest race), a highly miffed Ettore Bugatti was moved to observe that Bentleys were the fastest trucks in the world. That reputation is only reinforced at the first glance at this 1.7-ton behemoth, one of the 45 surviving road versions of the Blower.

The car was the subject of an Autocar magazine road test from 19 September 1930, although back then it had a different body. “The Appeal of Immense Power Linked with Great Docility,” summed up the test’s standfirst – they liked it.

Our test took place on last week’s Mille Miglia, the re-enactment of the famous 1,000-mile Italian road race that ran on 24 occasions between 1927 and 1957. First impressions are that although the replacement fabric-over-ash-frame body by Vanden Plas is minimal, the car looks enormous.

Which, at 14ft, 4.4inches long, it is. Most of the visual bulk is at the front, starting with the supercharger and tall radiator, so the impression is of a muscle-bound bulldog.

You have to shuffle bottom across from the passenger side into the driver’s seat and the dustbin-lid sized steering wheel sits in your lap. Green leather bucket seats are plumply upholstered and surprisingly comfortable. You can’t see the wings, although the massive headlamps help place the front. The enormous handbrake is outside the body and the four-speed gear lever is inside on the right.

Thankfully the throttle pedal has been converted from the centre to the right. You sit high and exposed, but the vistas across the roofs of the proletariat’s more modest transport stretch into the distance. At the wheel of the Blower you are gradually transformed into a character from those famous Russell Brockbank cartoons and find yourself pondering the advisability of a moustache and, perhaps, a pipe.

The dashboard is splattered with Jaeger and Smiths instruments including a chronometric revcounter that scurries up and down the scale like a frightened bird. Starting involves groping under the dashboard for the electrical master switch, pulling on a Bakelite fuel switch, tugging on the brass magneto switches and the ignition quadrant, then thumbing the big black starter. At idle, the engine sounds like chestnuts popping in the oven.

Bentley D-type gearboxes are not for the fainthearted and even experts rasp cogs – there’s a small time window to double declutch up or down. I never got from second to third completely, but experience breeds confidence and the clutch is light and positive.

Strangely, you don’t hear the supercharger from the driver’s seat, but the exhaust note more than compensates. The big four-pot blows a raspberry so rude it could come from a strip-club band. Where the Speed Six is refined power, the Blower is a brash hot rod.

At speed on one section we reached an indicated 85mph. The noise was simply shattering, spalling off the Armco, a bellicose blast across 83 years as redolent as Elgar’s Nimrod. With about 175bhp (the race cars had bigger SU carburettors and produced up to 240bhp) performance is brisk, but must have been unbelievable in 1930.

The nose surges forward in any gear and the big monobloc engine gains revs quite quickly and will rev as high as 3,500rpm. Even pressing on, however, you don’t need to take the dancing counter beyond 3,000rpm; the best work is done just below that, where the gears also seem happier to match speeds.

We got about 10.7mpg driving the wheels off – it doesn’t seem to burn fuel like a modern car, more devours it. While the engine is smoke-free, the Bentley leaves a trail of hydrocarbons and fried petrol in its wake.

As well as the gearbox, the steering dominates the experience. At rest, it’s so unbelievably heavy you shuffle it like a learner driver and manoeuvring is tough, especially with a 49ft turning circle.

On the move it lightens and is surprisingly accurate. It still tests the shoulders of a Bentley Boy or Girl and you have to be quick and accurate turning in before the suspension loads build and the chassis twists. After that you can only tug more lock on, which lifts you completely out of the seat like a parson sitting on a drawing pin.

The ride is pretty good and sleeping policemen can be taken at high speeds, but when you’re really on it, the beam axles start to work against each other making it feel quite fidgety. Understeer predominates, of course, but if the road is slippery, as it was on the way up to San Marino, the rear wheels will slide wide, which can be fun, but shouldn’t be overexploited – it’s virtually impossible to gather up a completely sideways Bentley.

The all-round drum brakes are unexpectedly powerful and largely fade-free, even over the infamous Futa Pass, and although you can usually get the Bentley stopped, at speed avoiding action is sometimes required to complement the brakes.

While the Blower Bentley has a brutish reputation, it is far from it. Driven with concentration and timing, as well as some concessions to its weight and shortage of grip, this old warhorse is still a quick machine and nailing it on a modern road is one of the most rewarding pieces of driving you’ll ever do.

It’s anthropomorphic, but it also feels like a living beast and even anoints you with its smell like a horse, a camel, or an elephant. After three days and 1,000 miles I smelled of a musty mix of high-octane exhaust, oil, brass and old leather; it’s pretty hard to wash out, but then I’m not sure I want to. Eau de Bentley is an exclusive and well-nigh irresistible scent.

This test is dedicated to Ian Moss, a great Yorkshireman and motor engineer, who died recently.