This is the Grandfather of Every German Sports Sedan

Photography by John Whitney Jr.

Ask any owner of a modern high-performance luxury sedan–a BMW M5, a Mercedes E63 AMG–what the grandfather of the high-performance luxury sedan is, and you’re sure to get the same answer: cars don’t have grandfathers. That’s because M5 and E63 owners can’t be bothered with frivolous things like riddles and hypothetical questions. They’re too busy talking on their phone at stoplights.

But if you want the answer to this question, I’m here to deliver it to you. You can trace the lineage of all of these cars, cars that have for years captivated the minds of drivers interested in combining high-performance and practicality, to the 1968-1972 Mercedes-Benz 300SEL 6.3.

For those of you who aren’t familiar with the 300SEL 6.3, a little background. To start this venture, Mercedes engineer Erich Waxenberger–reportedly after being told by a German car journalist that he was building “granny cars”–took an S-Class and shoved in the 6.3-liter V8 from the 600, a limousine that was, at the time, the largest Mercedes in production.

Now, by modern standards, a 6.3-liter V8 in an S-Class doesn’t seem so crazy. But back then, the S-Class only came with 6-cylinder engines. And they were slow, even by the standard of the time, with base-level 250S models offering just 130 horsepower and a 0-to-60 time of around 13 seconds.

So now imagine taking that car and shoehorning a powerful limousine engine under the hood. And I mean powerful: it made around 250 horsepower and–wait for it–369 pound-feet of torque. Inside, the SEL 6.3 was a staid, traditional-looking Mercedes sedan that might be purchased by your grandfather, who would promptly place a box of tissues on the parcel shelf. Same thing with the exterior. But under the hood, there was a monstrous V8 capable of sending the car to 60 mph in around 6.5 seconds and gluing the tissues to the rear window. It was Mercedes’ version of the muscle car.

So exciting was the 6.3 that famed Mercedes engineer Rudolph Uhlenhaut caught wind of the project and insisted on driving the car. As Waxenberger tells the story, Uhlenhaut drove the car for only a few minutes before getting out at a traffic light. There, he opened the hood, just to see what the hell was making this car go so fast – and how they were able to squeeze the huge motor into the engine compartment.

Given its unprecedented status, sales expectations for the 6.3 were low. In a 1999 article from Classic & Sports Car, Waxenberger recalls that the Mercedes-Benz sales department never expected to sell even 50 units. But, says Waxenbrger, “in the end, they sold so fast I couldn’t get one for my own test department.” Mercedes ultimately built more than 6,500 examples of the 300 SEL 6.3.

If you want to own a 6.3 now–and who doesn’t?–be forewarned that the sedan has a lot of potential issues that might throw off a casual buyer. Every single unit left the factory with air suspension, and–given that these cars were made from December 1967 to September 1972–even the newest ones are more than 40 years old, which might mean trouble. I’d be happy if the air suspension in my Land Rover lasted ten years, let alone forty. Beyond the suspension, the 6.3’s heating/air conditioning system is notoriously complicated. And, of course, the 300SEL includes a wide variety of other age-related issues likely to affect an older car.

But mark my words: one day, the 300SEL 6.3 will find its rightful place on Concours lawns as the performance sedan that started it all. And owners of M5s and E63s will likely walk right by, phone glued to their ear, searching for something flashier, unaware that they’ve just crossed paths with a legend: the grandfather of the performance sedan.