O. K. It is a 6 cylinder diesel. That makes it either a BD or its replacement the OC-12 IF the engine has ONE cylinder head. Now if the engine has 2 cylinder heads and each one is for 3 cylinders you either have aDD, FD (FDE) or an OC-15 or an OC-18. The FD and OC 18 models compare to a D-7 Cat so we are talking 90 Horse power!