Here are the serial number breakdowns for the 300 serial tractors. 300 Serial Numbers: 1975 = 30,001 - 55,000 (16hp Kohler Engines) 1976 = 55,001 - 70,000 (16hp Kohler Engines) 1977 = 70,001 - 80,000 (16hp Kohler Engines) 312 Serial Numbers: 1977 = 70,001 - 80,000 (12hp Kohler Engines)...