Some of the greatest enthusiast cars in history have come from the fruitful minds of engineers forced to work in secret to avoid the swinging axe of the bean-counters or judgmental frowns of pragmatic executives. This was the case with the Mercedes-Benz 300 SEL 6.3 and its creator, Erich Waxenberger. In the mid-1960s, the Mercedes-Benz lineup was very conservative. Even the SL sports car was limited to six cylinders and heavily biased toward automatic transmissions and luxury touring. Mercedes’ saloon car lineup was even more staid, with the W108 and its air-suspended sibling, the W109, topping out with a 3.0 liter, Bosch-injected inline six. Of course, these were wonderful cars built with exceptional attention to detail – they just lacked the performance that Waxenberger desired.

Working in secret and after hours, a small team led by Herr Waxenberger applied the classic American pony-car edict– “there’s no replacement for displacement” to the mid-sized W109, shoehorning in the all-alloy, 6.3 liter M100 V8 (lifted from the 600 grosser limousine). They handed the prototype over to long-time Mercedes-Benz executive, Rudi Ulehhaut who was seen as their best ally in getting this new project off the ground. Ulenhaut was so shocked by the turn of speed that it is said he immediately pulled over and opened the hood in disbelief at how Waxenberger and his team managed to fit such a beast of an engine in there. Give the M100’s output of 300hp and 434 ft-lbs of torque, it is easy to see how he was caught off guard! The project was green-lighted by Ulenhaut, with the unveiling scheduled for Geneva in 1968. The SEL 6.3 was a relative success with 6,500 examples built between 1968 and 1972. It also spawned smaller V8 engine models as well as a long tradition of big-engined, Mercedes saloon cars that continues to this day with the in-house AMG program. No car of its day could carry five passengers at such speed, and the handsome but conservative styling makes the “6.3” not only the ultimate Q-car, but one of the best all-out performance cars of the era.

Our featured example, a 1970 300 SEL 6.3, comes to us via a passionate and meticulous owner who cared deeply for the car while in his possession. In the same hands for the last 20 years, the prior owner purchased this car from the 2nd owner to use as a daily driver. He used the car regularly for many years, maintaining it carefully via specialists. As the duties of daily use showed their marks, he embarked on an extensive multi-year restoration in the early 2000s. In the process, corrosion was addressed using factory panels, the M100 engine was serviced with new timing chains, refreshed cooling system and other ancillaries, and the air suspension fully rebuilt. The quality of the restoration is exceptional, especially considering the costs involved in such a project. The bodywork is incredibly straight with outstanding panel fit and shut lines. The factory-correct and original color of 904G Midnight Blue Glasurit single-stage paint is beautifully laid down with a deep gloss and no flaws to speak of. The chrome bumpers, grille and exterior trim were restored to factory quality and the headlights converted to the more attractive European units. Factory “Bundt” alloys were restored and now wear proper Michelin rubber.

The quality and detail of the restoration continue to impress via the gorgeous interior. The front and rear seats were restored using parchment leather in correct materials and patterns, and a full set of complementary blue carpets set off the cabin beautifully. The wood trim was restored to concours standards, and the owner added wood A-pillar trim from a pre-1970 model as a subtle aesthetic upgrade. A rebuilt Becker radio keeps the dash looking period correct and all instruments, switches and even the air conditioning work as they should.

Nearly $100,000 was spent ensuring this car was returned to its former glory, all of which has been extensively documented in an included history file. The M100 engine is legendary for its longevity and the work performed ensured this car will have a solid future. The air suspension was serviced and rebuilt as needed, and the car sits properly, without losing air pressure over time. Even the differential and rear axle has been completely rebuilt at great expense using original MB parts.

Since the restoration, the owner ran the car and used it carefully but regularly to keep every system working as it should. He reported to us that a run from Eastern Pennsylvania to St. Louis, MO for the M100 owner’s club was relaxed and 100% trouble free. This 6.3 has also been shown at several events including the Greenwich Concours and the Deutsche Classic where it earned multiple awards. Few of these wonderful cars have been as cherished and well-maintained as this example. Considering the performance, quality and the outstanding restoration, this 300 SEL 6.3 represents an exceptional value that is a match for its exceptional performance.