A Very Brief History
The Mercedes-Benz Type 300 (chassis codes W186, W188, and W189) were the company's largest and most-prestigious models throughout the 1950s. Analogous to today's S-Class, the Type 300 cars were elegant, powerful, exclusive, and expensive.
Type 300 (W186 II) 1951-1954
The four door, six passenger Type 300 was available both as a saloon or cabriolet (officially called Cabriolet D).An all new three litre (2996 cc/182 in³) overhead cam, aluminum head straight-6 was coupled to a 4-speed all-synchromesh manual gearbox. Twin downdraft Solex carburetors made possible by an unusual diagonal head-to-block joint exploited oversized valves to produce 115 PS (85 kW; 113 hp).
6,214 saloon models and 591 Cabriolet Ds were produced until September, 1955 (including the 300b).
Type 300b (W186 III) 1954-1955
March 1954 saw power brakes introduced via a remote vacuum tank with the Type 300b. Vent windows were also introduced for the front windows. Power of the engine was upped to 125 PS (92 kW; 123 hp).
Type 300c (W186 IV) 1955-1957
A larger rear window was added in September, 1955 on the Type 300c. An automatic transmission was also introduced for the first time.
While the Cabriolet D was cancelled after June, 1956 (51 built), the saloon remained in production until July, 1957 and was built in 1,432 units.
Type 300d (W189) 1957-1962
Introduced in August 1957, the 300d was the linear successor to the 300c, with a longer wheelbase, fuel injection, and unique hardtop configuration transforming it into a pillarless phaeton. Employing a slightly detuned version of the 300 SL sports car's Bosch fuel injected engine, the 300d produced 180 PS (130 kW; 180 hp) at 5500 rpm. Automatic transmission was standard.
A total of 3,077 300d models was produced through March 1962, along with 65 special-order 300d-based Cabriolet Ds.
Type 300 S (W188 I) 1952-1955
The "W188" Type 300 S was Mercedes-Benz's top-end vehicle on its introduction at the Paris Salon in October 1951. The Type 300 S came as a 2+2 coupe, cabriolet (with landau bars) (officially Cabriolet A), or roadster. Although mechanically similar to the contemporary W186, the largely hand-built W188 was marketed as one of the top luxury cars in the world. 7.8:1 compression and triple Solex carburettors raised engine output to 150 PS (110 kW; 150 hp) at 5000 rpm.
From July, 1952 to August, 1955, a total of 216 Coupés, 203 Cabriolet As and 141 Roadsters were produced.
Type 300 Sc (W188 II) 1955-1958
1955 saw the substitution of Mercedes-Benz's "low-pivot" independent suspension in the rear, and the addition of fuel injection in the Type 300 Sc whose inline-six now delivered 175 PS (129 kW; 173 hp) at 5400 rpm. Visually, a pair of chrome strips on either side of the hood denotes this "Sc" model.
98 Coupés, 49 Cabriolet As and 53 Roadsters were built until April 1958.
From wikipedia.org