1938 M-B 540K Sindelfingen Cabriolet “A”

Sixteen years after its restoration, it actually looks like a car again, rather than something embalmed for open-casket burial

by Raymond Milo with Kathleen Donohue

Together with its predecessor the 500K, the magnificent Mercedes-Benz 540K was arguably the most noteworthy production model offered by the Stuttgart firm during the 1930s. A development of the 500K, whose independently suspended chassis it shared, the 540K was powered by a 5.4-liter supercharged straight-eight engine. It featured the company’s Roots-type supercharger system, in which pressing the accelerator to the end of its travel would engage the compressor and close off the atmospheric intake. Launched at the Paris Salon in October 1936, the 540K developed 155 hp unsupercharged or 180 hp with the supercharger engaged. The gearbox was a four-speed, but with direct final drive, unlike the overdrive in the 500K. With the supercharger engaged, the 540K’s top speed approached 110 mph, matched by servo-assisted brakes. Tested by Britain’s Motor magazine, the 540K was judged to have lighter steering and handling than its predecessor and a more comfortable...