It was 1980 to 1982, all cars in the US by federal law had to have an 85mph speedo, even corvettes, porsches and lamborghini's.

Also, your oil/temp/fuel cluster has black needle centers, while your tach and speedo have silver ones. I think your speedo was replaced at some time or another, from a 77 to 79 240D or 300D.

John