2600, 2310, 2810 Series Tractor (1/1975 to 2/1990) 158 CID 3 Cyl Diesel 4.2 Inch Bore, 3.8 Inch Stroke, 2.9645 Inch Compression Distance. BOK Engine kit numbers consist of: Pistons, Piston Pins, Rings, Rod Bearings, Main Bearings, Full Gasket Set, and Seals. VOK Valve Train kit numbers consist of: Intake and Exhaust Valves, Valve Springs, and Valve Keepers.