Mercedes-Benz was coupe-focused at this year’s Pebble Beach Concours – with a number of sexy back catalog models reinforcing the gravitas of the just-launched S-Class Coupe and S63 AMG Coupe’s on display.

These can be called “Coupes” but they are fancier and more fun as “Coup-pays” — pronouncing the accent over the “e” like the Europeans do.

None drew more stares than this one-off 1938 540K Streamliner, which feels many years younger than its 1938 build date would suggest.

The most striking elements of the hyper-flowing panels are:

• — the sheer scale of the machine from tip to tail, and tire to roof, is immense. the 540K absolutely dwarfs the SL from the 1950s, and must weigh nearly three tons. It is much larger and just as tall as the Concept Coupe SUV from Beijing sitting nearby, for example.

• — This scale is virtually un-fetted by shut-lines or panel gaps: the body is either made of huge hand-shaped aluminum panels, or its edges and seams have been welded and polished to perfection to give this illusion. Both are likely true.

• — the glasshouse is decidedly modern, showing much of the “helmet visor” look of the latest Koenigsegg and Nissan GT-R, with glass that is curved wildly using aeronautics methods. Other cars at this time still used flat glass where-ever possible to save cost. Much as the “fighter jet airplane” design note is a cliche today, this is an authentic use of fighter plane parts suppliers.

• — The rear-hinged coach doors are decadent and unique, as is the front lighting and other detailing that owes more to the autobahn top-speed-record cars than the production Mercedes-Benzes of the day.

Overall, the 540 K Streamliner is quite a presence. It is an important car — and one that shows the long tradition of Mercedes-Benz at the top of the ultra-lux GT coupe market.

As well as inspiring the production S-Class Coupe and others, the 540 K Streamliner has a direct lineage link to the AMG Vision Gran Turismo and the forthcoming AMG GT set to replace the SLS for 2015. Exciting to meet such a car from Mercedes – and we’re grateful they brought it to Pebble Beach.

Official Details below from Mercedes-Benz Classic.

1938 Mercedes-Benz 540K Streamliner

Unique one-off model takes center stage at Pebble Beach: the 540 K Streamliner from Mercedes-Benz Classic

Mercedes-Benz Classic

August 05, 2014

• Public premiere for this trendsetting one-of-a-kind model dating from 1938

• In addition: Mercedes Grand Prix racing car of 1914 recalls historic one-two-three victory of 100 years ago

Stuttgart. – Mercedes-Benz Classic will showcase the 540 K Streamliner at this year’s Pebble Beach Concours d’Elégance. Following extensive restoration and reconstruction, this extraordinary vehicle dating from 1938 will celebrate its international public premiere on the west coast of America. The 540 K will also participate in the Tour d’Elégance on Thursday 14 August, and exhibited at the Concours d’Elégance on Sunday 17 August.

“The 540 K Streamliner represents the embodiment of perfection in its purest form”, says Michael Bock, Head of Mercedes-Benz Classic and Customer Center. “The integrity of its overall design as well as numerous technical details do not only epitomise the innovative power of the Mercedes-Benz brand but also its expertise in the development of one-off vehicles to meet the very highest expectations in terms of design, comfort and customer benefit.”

This exceptional vehicle was built with a powerful supercharged engine for high-speed, long distance motoring. Thanks to its lightweight aluminium bodyshell developed in the wind tunnel, the 540 K Streamliner is an object lesson in efficiency for its size class. In addition to its lightweight construction and sophisticated aerodynamics, it is the car’s outstanding exterior and interior design, elegant appointments and spaciousness that make the 540 K Streamliner such a very special vehicle.

As part of a complex and time-consuming project, Mercedes-Benz Classic restored and rebuilt the vehicle to its original condition, using only the technical skills, methods and materials of the period from which the vehicle originates.The result is a spectacular, one-of-a-kind vehicle, as it was in 1938: a herald of the future, combining innovative 1930s vehicle design with exceptional efficiency and a sophisticated, sleek aesthetic appeal.

The Mercedes-Benz Classic vehicles at the Pebble Beach Concours d’Elégance 2014

Mercedes-Benz 540 K Streamliner, 1938

The Mercedes-Benz 540 K streamlined saloon was developed in 1937/38 in the special vehicle production unit at the company’s Sindelfingen plant in the style of a Gran Turismo, although the conventions of the 1930s meant that the designers described this body shape as a streamlined saloon, or quite simply ‘Streamliner.’ Based on a chassis from the standard-production 540 K model, a powerful supercharged engine would accelerate rapidly for sustained high-speed travel over long distances. Thanks to its lightweight aluminium bodyshell, developed in the wind tunnel, this unique vehicle is an object lesson in efficiency for its performance category.

In addition to its lightweight construction and sophisticated aerodynamics, the car’s outstanding exterior and interior design, elegant appointments and spaciousness distinguish the 540 K Streamliner as a very special vehicle. It was originally designed to take part in the long-distance Berlin-Rome race, planned for the autumn of 1938. This was initially postponed until 1939 and then ultimately cancelled completely due to the outbreak of the Second World War.

From mid-1938 onwards, the streamlined model was used by the German branch of tire manufacturer Dunlop for the relentless everyday testing of high-speed tyres for fast cars. Mothballed after the war, 2014 sees it thrust into the limelight once more following a full restoration to its original condition.

As part of a complex and time-consuming project, Mercedes-Benz Classic has restored and rebuilt the vehicle to its absolute original condition, and has done so using only the technical skills, methods and materials of the period from which the vehicle originates. The search for information in the archives produced important documentary evidence, with the end result culminating in a spectacular one-off vehicle. The Streamliner thus stands today as it was when first seen in 1938: a herald of the future, whose stunning bodyshell makes high driving speeds and exceptional performance seem perfectly credible, even before it moves an inch.

Technical data

Year of construction: 1938
Cylinders: 8/in-line
Displacement: 5401 cubic centimetres
Output: 85 kW (115 hp), with supercharger 132 kW (180 hp)
Top speed: 185 km/h