Actually Daimler Benz had already achieved everything. The preliminary final step was the record of Rudolf Caracciola, the reached 432 km/h on the closed-off motorway Frankfurt-Darmstadt in 1938. Bernd Rosemeyer died when he tried to win back this record for the Auto Union. This ensured that it was a record for a longer time.
But enough seems not enough the people of Mercedes. For one, they wanted to push themselves a little between the very successful connection of Ferdinand Porsche to Auto Union, on the other hand they had successfully changed just a 44 liter aircraft engine on gasoline direct injection, the first ever. The installed into a vehicle and then surpass the currently increased record of 595 km/h by John Cobbat, that's the idea.
The Porsche company was open to all construction orders, actually thereof depending. So one took the challenge to bring briefly the existing engine DB 603 with help of a turbo driven by the crankshaft even to 2,570 kW (3,500 hp). Porsche still really needed 'only' to construct the right car.
The year before, the Porsche team had constructed a mid-engine car with a double, each of driven rear axle, which got along with only one instead of possibly two engines of 3000 kg. Of course, the car had the in-house torsion bar suspension, but also dampers based on both friction as well as hydraulic. If it would not have two rear axles, for example, it would have been equal to the Silver Arrow of Auto Union with its swing axles.
The wheels were huge though, probably a tribute to the load of the tyres with such a record attempt. In order to protect the tyres, the car had a centrifugal clutch, the should avoid any slip when moving off. As a cross between dry and wet friction it prevented occurring slip. Since no gear was present, it had to do it up to 200 km/h (= 1,000 rpm). The clutch lining was correspondingly stable.
The record should be achieved as well as that of John Cobb on the Bonneville Salt Flats in distant U.S. state of Utah. Hans Stuck should drive, actually under contract at Auto Union, the also supplied the idea for this. Stuck was indeed able to chalk up records eg on Auto Union vehicles and motor boats but as a top racing driver now no longer undisputed. Unfortunately, one wrote at the completion the far advanced year 1939.
There was confusion about the length of the track, which was necessary to achieve and maintain 650 km/h. In the opinion of some experts were not enough, the approximately 20 km from Bonneville. At the additional width of the car by drift generated wings, one highway side was not wide enough. The highway Halle-Dessau, equipped with a drivable green stripe in the middle was already proving as too short during trial runs with less speed.
Of course, by outbreak of the war 1939, it was impossible to imagine a trip to America. John Cobb succeeded only in 1947, his own record to improve to nearly 640 km/h. Whether Daimler Benz really wanted the record or only wanted to entice Auto Union the Professor Porsche, remains unexplained. 12/13