Welcome to the Hooniverse Obscure Muscle Car Garage, a regular feature which aims to expand the notion of what a muscle car is, and to shoot bullet-holes in conventional thinking while we’re at it. This particular featured car should stir up a lot of debate, not only because of its debut in 1975, but also because it was built in Germany. Without further delay, I present the Mercedes-Benz 450SEL 6.9. The 1975-1980 Mercedes-Benz 450SEL 6.9 was a continuation of the big-engine S-class sedan, now built on the W116 platform introduced for 1973. Considerably changed from its predecessor, it featured somewhat lower and sleeker lines that were still distinctly Mercedes. 1975 was a lousy time for performance cars when Mercedes introduced its flagship model, powered by a monster 6.9-liter V-8 (roughly 420 cubic inches). The engine pumped out 280 horsepower and 405 pound-feet of torque. This Mercedes could launch from 0-60 in around 7 seconds and could run 140 mph all day long, while maintaining a refined and quiet passenger compartment. Topping out at 150 mph or higher was never out of the question. The engine is related to the original 600 limousine unit, though there were numerous modifications such as Bosch K-Jetronic fuel injection, breakerless electronic ignition, dry-sump lubrication, and hydraulic valve gear actuation. The suspension was shared with lesser-powered S-class models (lower A-arms, upper transverse links, and anti-roll bar in front; semi-trailing arms and anti-roll bar at the rear), but springing was now provided by hydropneumatic oil/nitrogen struts instead of standard steel units used in other S-class models. Rear-end self-leveling was incorporated to compensate for a heavy load of luggage or passengers. The revised chassis gave unbelievable handling and roadholding for such a large and powerful car, plus the advantages of a softer ride. It came only with a three-speed torque-converter automatic transmission. Fast but thirsty, the 6.9 was launched a good three years after the rest of the W116 range because of Mercedes’ sense of propriety in the wake of the 1973-1974 Arab oil embargo. When fuel prices “destabilized” again in 1979, U.S. fuel economy standards were in force, which made the 6.9 something of a liability here in the US. The model was dropped after 1980. Still, this was the fastest version of what was widely considered “the best sedan in the world,” which sounds appropriate for a Muscle Car, don’t you think? Not impressed? Consider that the 450SEL debuted more than 33 years ago, and in a completely different automotive climate than either the late 60′s, when horsepower was king, or today’s environment, in which you can get the same horsepower in a V6 Honda Accord. High performance is almost commonplace today, but it was very nearly dead in the mid-1970s. Even the cars that pretended to be fast (of which there were many in 1975), were often sporty two-door coupes with tacky detailing. Sedans were strictly dishwater-dull, meant only for families or for showing off at the local marina. This was decades before Mercedes brought AMG in-house to create super sedans, before Audi introduced its hot-rod S and RS series, and BMW M-Sport began cranking out legendary vehicles. In this climate, Mercedes married Corvette- and Trans-Am-humbling performance with Mercedes-Benz civility in a refined package that is still legendary today. Combine the 6.9′s power with its under-the-radar appearance, and you get the king of all sleepers. And that is a true Obscure Muscle Car. So, there you have it. Is the Mercedes-Benz 450SEL 6.9 an Obscure Muscle Car that belongs in the Garage, or should it just go back into that well-manicured stable where thoroughbreds belong? Debate away, and let me know what you think… or should I just check into the insane asylum? [poll id=”210″] Please Note: All Images are screen grabs from around the web. If you want credit for any image, please let me know in the comments section. Thank You!