Mercedes 230SL

Some models in the 1950s also had lower-case letters (b, c, and d) to indicate specific trim levels. For other models, the numeric part of the designation does not match the engine displacement. This was done to show the model's position in the model range independent of displacement or in the price matrix. For these vehicles, the actual displacement in liters is suffixed to the model designation. An exception was the 190-class with the numeric designation of "190" as to denote its entry level in the model along with the displacement label on the right side of the boot (190E 2.3 for 2.3-litre 4-cylinder petrol motor, 190D 2.5 for 2.5-litre 5-cylinder diesel motor, and so forth). Some older models (such as the SS and SSK) did not have a number as part of the designation at all.