Without the Mercedes 300SEL 6.3, There Wouldn’t Be an AMG

While it’s cutting cars in favor of SUVs and crossovers, AMG is still producing incredibly-fast Mercedes models. For example, the Mercedes-AMG GLS 63 can out-accelerate a Corvette. And in the early 2000s, the E55 AMG was the fastest production sedan on the planet. But, while the tuner’s history contains some oddballs—like a 500-hp minivan—and even a Mitsubishi, it all started with one sedan: the Mercedes 300SEL 6.3.

The Mercedes 300SEL 6.3 is a German luxury sedan hot rod sleeper

1956 Mercedes 300SL Gullwing rear
1956 Mercedes 300SL Gullwing rear | Bring a Trailer

Mercedes has an extensive racing history, as evidenced by the 300SL Gullwing. However, following a rules change, the automaker withdrew from motorsport in 1965, Car and Driver, and Autocar report.

A black-and-white photo of the 1968 Mercedes 300SEL 6.3's engine bay
1968 Mercedes 300SEL 6.3 engine bay | Daimler

This wasn’t a problem for its sedans, which were more about well-built luxury than outright speed. However, one engineer, Erich Waxenberger, was secretly trying to give the brand a performance injection, Top Gear reports. Starting with a 1960s W109 sedan, Waxenberger removed its six-cylinder engine. And he installed the 6.3-liter V8 from the larger and heavier 600 ‘Grosser’ sedan, then the most expensive car in the world.

According to legend, his boss, Rudi Uhlenhaut, borrowed the ‘prototype’ for a test drive, Hagerty reports. He then immediately pulled over to see what kind of engine the sedan had. When he got back, Waxenberger’s secret project was approved.

The result was the 1968 Mercedes 300SEL 6.3. Externally, little separated it from its six-cylinder brethren. But under the hood, its mechanically fuel-injected V8 developed 247 hp and 369 lb-ft. That’s sent to the rear wheels via a 4-speed automatic. And despite weighing almost 3900 pounds, the Mercedes 300SEL 6.3 can go 0-62 mph in 6.3 seconds, Hemmings reports. Its 142-mph top seed also made it the fastest production sedan in the world. Basically, it was the E55 AMG and Charger Hellcat Redeye of the 60s.

The tan-leather interior of the 1968 Mercedes 300SEL 6.3
1968 Mercedes 300SEL 6.3 interior | Daimler

That high curb weight is due to the Mercedes 300SEL 6.3’s luxury features, which are fairly advanced for the time. This sleeper sedan has 4-wheel vented disc brakes, power steering, power windows and locks, and self-adjusting air suspension. And the options list includes things like A/C, a power-operated sunroof, and folding rear tables.

But AMG and Waxenberger thought it could go even faster.

The first AMG: the 1971 Mercedes 300SEL 6.8 ‘Rote Sau’

At roughly the same time as Waxenberger was developing the 300SEL 6.3, engineers Werner Aulfrecht and Erhard Melcher were leaving Mercedes. The duo had worked in the automaker’s racing program before it shut down. Because they wanted to keep racing, they set up shop in an old mill on the outskirts of Stuttgart. Taking the first letters of Aulfrecht, Melcher, and Aulfrecht’s birthplace, Grossaspach, AMG was born in 1967.

At first, AMG worked on customer’s Mercedes, much like Alpina did with BMWs. Then in 1969, the tuner purchased 2 damaged 300SELs, RM Sotheby’s reports. But they weren’t 6.3s, but rather 6.8s. Waxenberger had attempted to take the sedan racing, and even won the 6 Hours of Spa, but was stymied by lack of suitable tires. And Mercedes didn’t want him to continue. So he and AMG decided to work together.

The result was the 1971 Mercedes 300SEL 6.8 AMG, aka ‘Rote Sau,’ or ‘Red Pig.’ The sedan now featured aluminum doors and magnesium wheels with wider tires. It also had a heavy-duty differential, a racing exhaust, an extra oil cooler, and stiffer suspension. Plus, under the hood was a 6.8-liter V8, rated at 430 hp and 450 lb-ft, Motor Trend reports. Initially, it was fitted with a modified automatic, Hagerty reports, but later received a 5-speed manual.

As a result of all this, the Mercedes 300SEL 6.8 AMG weighed about 3500 pounds. And with the extra power, it could go 0-60 in 4.2 seconds and reach a top speed of 165 mph. It was called ‘Red Pig’ in jest due to its color, weight, and fairly-large dimensions. But it was still fast enough to take 1st in class and 2nd overall at the 1971 24 Hours of Spa.

Getting one today

Unfortunately, the original Rote Sau was sold to French manufacturing company Matra for aircraft-part testing. However, Mercedes modified an original 300SEL 6.3 into a Red Pig replica. The Mercedes Classic Center then created ‘Silber Sau,’ or ‘Silver Pig,’ MT explains, which is even lighter and sportier.

Because of its iconic status, a few people have created Mercedes 300SEL 6.8 AMG replicas of their own. And one even sold at a February 2020 RM Sotheby’s auction for the equivalent of $510,990.

The rear-3/4 view of a light-brown 1969 Mercedes 300SEL 6.3 sedan
1969 Mercedes 300SEL 6.3 rear | Bring a Trailer

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Luckily, getting a Mercedes 300SEL 6.3 is a little easier on the wallet. Although examples have sold for as much as $70,000 on Bring a Trailer, $40,000-$50,000 is the usual average price. And as of this writing, there’s a 1969 example listed at $15,995. That makes this proto-AMG more affordable than some modern AMGs.

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