not ure on the smaller machines, but If I remember right, from a 9760 to a 9860 the larger unloading auger is standard insted of an option, the rotor drive belt and sheaves are bigger, drivelines to the primary countershaft are heavier, larger fuel tank, heavier duty reverser standard instead of an option, conture master standard equipment, also heavy duty final drives. Now they have change some of the options to standard equipment this past year on the 9760 so I am not quite shure where those diferences are, some one should have a better memory on this. Some guys say the 9760 was running out of power in heavy wheat with a 35 foot header. depends on how hard you want to drive.