MITSUBISHI FUSO FIGHTER with the 6D1 series engines are very popular and are trading at high prices even on trucks that are about 30 years old. The 6D1 series engines was an engine for medium-duty trucks that appeared in 1974, and there were 6D10 (5,974cc), 6D11 (6,754cc), 6D14 (6,557cc), 6D15 (6,919cc), 6D17 (8,201cc), etc.