KelB - 5/16/2016 13:35 I know there is no substute for cubes in durability however where does the line cross. I'm not sure about that. The engine will be designed for a certain duty cycle and life expectancy and within reason, I can't see why the displacement would have much effect on the life of the engine. Deere sold 2 versions of the 7820. The NA model had the 8.1, the model that crossed the Atlantic for Europe had the 6.8. The 6.8 had slightly more power, slightly more torque at slightly lower revs and slightly better specific fuel consumption. Aside from all that the bigger engine was better, or something. | 
Fuel usage per Horse power gal/hour etc
