My buddy Syed over at the IEDEI blog made mention of the Mercedes C111-3 prototype, and noted its similarity to the Silver Arrows of the 1930s. In particular, I was struck by the commonalities between the winged version of the C111 (above) and the Mercedes T-80 (below). Few people know that the T-80 was actually engineered by Ferdinand Porsche -- despite designing grand prix cars for Auto Union, he was also secretly working closely with driver Hans Stuck and the highest echelons of the German government on this Mercedes record-breaker. In the end, this 2-engined behemoth was never run in anger.
There was no straight road large enough in Germany to handle the T-80's intended speeds, and German officials realized that a trip to the Bonneville salt flats was a tricky proposition given the political climate of the time (there had been anti-Nazi protests when the German cars showed up for the Vanderbilt Cup, but Bernd Rosemeyer won it anyway). Add to all this the fact that John Cobb's Railton Special broke the 350 mph barrier in late 1938 during the construction of the T-80, surpassing all the targeted specifications of the Mercedes. Finally, as they scrambled to redesign the car to break Cobb's record, the outbreak of the War sealed its fate. The much smaller C111 (above) was created in the more peaceful 1970s, and was never aimed at the outright Land Speed Record, but it did break several records for Diesel powered vehicles.
Citation: Mercedes T-80