In April 1971, the Mercedes-Benz 350 SL debuted, immediately capturing the attention of car enthusiasts. This powerful and sophisticated roadster was praised for its well-proportioned design and the inclusion of a stylish, removable hard top. Beyond its elegance and build quality, the 350 SL also prioritized safety, boasting crash performance that was remarkably advanced for its time. Underneath its long hood resided the first eight-cylinder engine ever fitted in an SL model, marking a new era for this iconic vehicle.
The Decision that Shaped a Generation
While officially launched as the ’71 SL, internally designated as the R 107, its origins trace back to June 18, 1968. This was the date when the Executive Board, after considerable debate, greenlit the car’s production. A key point of contention was whether to develop a coupe with a sliding roof instead of a roadster. Concerns were rising in the USA regarding the safety of open-top vehicles. This decision to proceed with a roadster, reminiscent of its predecessors, hinged on the strong advocacy of Dr. Hans Scherenberg, head of development. He later recalled, “The SL gave me great pleasure but also cost me a great deal of effort. We didn’t reach this decision easily.”
The question of a coupe variant remained. Discussions continued about a potential four-seater sports coupe based on the R 107 platform, or an “image coupe” derived from the upcoming S-Class, potentially arriving in the mid-1970s. Karl Wilfert, head of body design in Sindelfingen, proactively developed a coupe design based on the R 107. Initially met with resistance, Wilfert’s persistence led to the eventual approval of his sports coupe concept, which became the successful Mercedes-Benz SLC.
Adding to its appeal, the 70s Mercedes SL boasted the quickest and simplest soft top mechanism among convertibles and roadsters, a cleverly designed system that was entirely manual and remarkably efficient.
Setting New Standards in Roadster Safety
The 1971 SL incorporated Béla Barényi’s pioneering safety principles, featuring front and rear crumple zones and a rigid passenger cell – the “three-box principle.” Unlike its predecessor which used a modified saloon floorpan, the R 107 utilized a dedicated, robust frame structure. This included an enclosed transmission tunnel and box-section cross-members and side members, engineered with varying metal thicknesses to ensure controlled deformation in a collision.
Since the SL was conceived as a true open-top car, eschewing a Targa-style roll bar, the A-pillars and windscreen were crucial for rollover protection. These components were significantly enhanced, offering 50 percent greater strength than previous designs. Furthermore, the windscreen was bonded to its frame, further increasing structural integrity. These advancements resulted in exceptional performance in roof drop tests, satisfying US safety standards for open-top vehicles even without a roll bar. The hard top’s rear window was also bonded for added safety.
Interior Design Focused on Safety and Comfort
The interior of the 70s Mercedes SL showcased groundbreaking safety innovations. The instrument panel was designed to absorb energy and was generously padded with foam on both the upper and knee-level areas. Another notable innovation was the newly designed four-spoke steering wheel, a product of accident research findings. While retaining the proven impact-absorbing boss, the rim, padded face, and boss were now encased in polyurethane foam. A telescopic safety steering column and the positioning of the steering gear behind the front axle further enhanced safety.
Beyond safety, the interior prioritized driver and passenger comfort. The three dial instruments were exceptionally clear and easy to read, complemented by ergonomically designed controls. Seats were equipped with head restraints and automatic seat belts as standard. For those desiring extra space, an optional “sitting space” could replace the standard luggage area behind the seats, though its practicality was limited.
Climate control was also advanced for the era, featuring a highly responsive heating system operating independently of back pressure, controlled by flaps, and supported by an innovative heating and ventilation system integrated into the doors. A rechargeable torch in the glove compartment was a thoughtful addition. Dirt-repellent claddings on the A-pillars and exterior mirrors maintained good visibility even in adverse weather. The centrally positioned windscreen wipers provided an impressive 70 percent coverage, remained optimally positioned in the airflow, and stayed firmly planted even at high speeds.
An Instant Classic and Bestseller
Despite its advanced safety features, the immediate popularity of the new 70s Mercedes SL stemmed from its striking design as a premium open-top car, a unique offering in series production at the time. Its distinctive front end, featuring the iconic SL grille, wide-band headlamps, and ribbed indicator lenses, conveyed power and presence. The low-slung silhouette was elegant with the top down and equally refined with the hardtop installed. The subtly concave trunk lid was a nod to the “pagoda” SL era. The robust, ribbed wide-band rear lights added a masculine touch to the rear design. Furthermore, the SL’s soft top was renowned for being the fastest and easiest to operate, a purely mechanical design that folded neatly beneath a cover, just like its predecessors.
Engine Options Across its Production Run
Throughout its remarkably successful 18-year production run, exceeding initial plans, the 70s Mercedes SL offered a diverse range of six and eight-cylinder engines, resulting in varied model designations. At launch, the SL featured the familiar 3.5-liter eight-cylinder engine, already acclaimed in the 280 SE 3.5 coupe and convertible since 1969. Producing 200 hp at 5800 rpm, it propelled the nearly 1600 kg SL from 0 to 100 km/h in 9 seconds, reaching a top speed of 210 km/h, a significant improvement over its predecessor.
The six-cylinder options included the 280 SL (185 hp, 1974-1985) and the 300 SL (188 hp without catalytic converter, 180 hp with, 1985 onwards). These offered similar performance to the smaller eight-cylinder models but were more economical and less expensive. The eight-cylinder lineup began with the 200 hp 350 SL (1971-1980). The more powerful 450 SL (from March 1973) delivered 225 hp. In 1980, the 500 SL arrived with a lighter all-alloy engine producing 240 hp, later upgraded to 245 hp in 1985 with improved fuel efficiency, remaining until production ceased in 1989.
The 350 SL was succeeded by the 380 SL in 1980, and in 1985, the 420 SL was introduced, offering 218 hp (without catalytic converter) and 204 hp (with). A unique variant was the 560 SL, exclusively for the US market, featuring an “American” catalytic converter and producing 230 hp.
The Birth of the SLC Coupe
In 1961, Mercedes-Benz had introduced both coupe and convertible versions based on the “fintail” platform. As the new S-Class platform was not ready in the early 1970s to underpin a new coupe, the SL platform became the basis. Karl Wilfert’s advanced coupe design was ready for realization. The SLC, officially named “sports coupe,” premiered at the Paris Motor Show in October 1971. Up to the windscreen, it mirrored the roadster, but then diverged with a longer wheelbase and a fixed roofline. The four-seater cabin was topped by a gently curved, flat roof flowing into a large, heavily inclined rear window. This gave the rear a more substantial appearance, with a slightly convex boot lid compared to the roadster.
The SLC’s increased length was evident in its longer wheelbase (2820 mm vs. 2460 mm) and the design of the side windows, intended to be fully retractable without a B-pillar, a hallmark of Mercedes-Benz coupes. However, the short distance between the door and rear wheel arch posed a challenge for retracting the rear side windows. Wilfert’s innovative solution was the distinctive, double-glazed “sidelights” with integrated louvres. These divided the side windows, making them smaller and easier to lower, though stylistically controversial. The SLC also pioneered the placement of the standard first-aid kit in a dedicated compartment beneath the rear window, a feature adopted in all subsequent Mercedes-Benz models.
Produced from 1971 to 1981, the SLC was available as the 280, 350, 380, 450, and 500 SLC, sharing engines and transmissions with the SL roadster. An exception was the 450 SLC 5.0 (1978-1980), which debuted the new five-liter V8 light-alloy engine. This model also featured a front apron and rear spoiler made of contoured rubber, a first for the 107 series. The SLC’s drag coefficient was significantly better than the SL’s, enabling comparable performance despite a slight weight increase. Over its ten-year run, 62,888 SLCs were sold, proving its popularity as a “sports coupe,” further cemented by Mercedes-Benz’s rally successes with the model.
Rallying Heritage of the 70s Mercedes SLC
After a period away from motorsport, Mercedes-Benz’s return in 1977 saw significant success in the London-Sydney long-distance rally, securing first, second, sixth, and eighth places. The 280 E and 450 SLC 5.0 were chosen for further rally endeavors in 1978. Closely resembling production models, they required modifications like long-range headlamps, raised suspension, roll cages, and additional fuel pumps. A dedicated team led by Erich Waxenberger aimed for victory to uphold the company’s reputation.
The “Vuelta a la Americana Sud” rally in 1978, covering almost 30,000 km across South America, resulted in a dominant Mercedes-Benz performance, taking the top five positions. The 450 SLC 5.0 claimed first, second, and fourth, while the 280 E took third and fifth. The 1979 East African Safari followed, with the 450 SLC 5.0 achieving second and sixth place, and the 280 E fourth, despite challenges. The 1979 Bandama Rally in Ivory Coast saw a Mercedes-Benz quadruple victory. In 1980, a re-engineered 450 SLC 5.0, lighter and with wider tires, participated in the Portuguese Rally, achieving fourth and fifth places. The Kenya Safari of the same year resulted in third, sixth, and tenth places.
The Acropolis Rally proved challenging, with only minor rankings due to various mechanical issues. At the Codasur Rally in Argentina, one team secured second place. The Rally of New Zealand presented unique challenges for the large 500 SLC, yet the team achieved fourth and fifth place through sheer determination. The Bandama Rally in December brought another double victory, with a high percentage of SLCs finishing despite the rally’s demanding terrain. This marked the end of Mercedes-Benz’s factory rally involvement at the close of 1980.
A Lasting Legacy
The 70s Mercedes SL, starting as the 350 SL in 1971, became a legend over its 18-year production run. As the most successful Mercedes roadster to date, with 237,297 units produced, it achieved classic status even during its production. Its design, featuring a hardtop with a subtle pagoda-style roof and a gently concave trunk lid, contributed to its character, even if slightly impacting aerodynamics. Crucially, the 70s SL introduced features like an eight-cylinder engine, catalytic converters, and ABS, solidifying its place as a pioneering and desirable classic Mercedes-Benz.
daimler ag photography/daimler ag and mercedesheritage
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