OM904 different serial number compatibilty and respecification
The first 6 digits of the serial number define the base hardware & emission compliance, (for example a 904.971 is EU Stage IIIA and a 904.946 is EU Stage 2).Differing base hardware configurations cannot be converted - the solution to that is to request the required engine specification from MTU. Typically this will be done as a reman engine if the model is no longer offered by MTU.