Mercedes-Benz 300 SEL 6.3
A quiet luxury sedan borrowed the giant V8 from Mercedes-Benz's 600 limousine and suddenly had the speed to surprise sports cars on the autobahn.
1968 Mercedes-Benz 300 SEL 6.3 cover · Charles from Port Chester, New York · CC BY 2.0
More than a set of wheels.
Mercedes-Benz unveiled the 300 SEL 6.3 at Geneva in March 1968. Test engineer Erich Waxenberger had first squeezed the M100 V8 from the huge 600 into the smaller air-sprung W109 body, proving that limousine power could create a discreet high-performance sedan. Production cars kept the four doors, wood-trimmed comfort and self-leveling ride while adding 250 PS and enormous pace. Mercedes-Benz built 6,526 through 1972, establishing a pattern for the brand's later fast luxury sedans.
Look a little closer.
Early test cars were so discreet that Mercedes-Benz's own archive jokes about Porsche 911 drivers wondering why an innocent-looking sedan had just disappeared ahead of them.
Photos show an example of the model or generation. The pictured vehicle’s year, equipment, or modifications can differ from the specification described here.
The prototype that announced itself by sound
Waxenberger began the V8 conversion before passenger-car development chief Rudolf Uhlenhaut had formally approved it. The story says Uhlenhaut heard the prototype's deep rumble passing his office, summoned the engineer and then authorized further development. That unofficial experiment became the 300 SEL 6.3 shown at Geneva.
Source: Mercedes-Benz Media · 300 SEL 6.3 world premiere history ↗Speed without shouting
The 6.3 looked much like another W109. A small boot badge, twin halogen headlamps, auxiliary fog lamps, a higher-reading speedometer and a tachometer were the clues. Underneath, however, it combined self-leveling air suspension, ventilated discs at all four wheels, power steering, a limited-slip differential and the 600's V8—an unusually complete high-speed package for 1968.
Source: Mercedes-Benz Media · W108/W109 60th anniversary ↗Where these facts come from
- Mercedes-Benz Media · 300 SEL 6.3 world premiere history
- Mercedes-Benz Media · W108/W109 60th anniversary
- Mercedes-Benz Public Archive · type 300 SEL 6.3
- Mercedes-Benz Media · Solitude Revival technical summary
Selected facts checked for this edition. Some source pages link to broader model families. Last reviewed October 1, 2026.