A Corn_Soybean Special machine contains additional options to the base machine. Unlike the K owner manuals, the K2 owners manuals list the optional accesssories available plus the Corn_Soybean Special specifications. A 1978 K2 Corn_Soybean Specifications are as follows: COMBINE -Perforated panels, (unload auger, return, shoeIJ) -Straw Walker Risers -Hyd. V-Speed Reel Drive and Reel lift -Forged feeder beater fingers guides and .625" dia fingers -Chaffer, Round end, Deept tooth, 1.62" spacing -Cylinder speed Kits: 390-595rpm and 599-915rpm HEADERS, -10,12,and 13ft -Hydraulic reel lift and v-speed drive w_ dual ranges -Heavy Duty pickup reel w_ fine adjustment and lift ram safety latches -Rock guards -Heavy duty chrome sections OPTIONAl EQUIPMENT -Square end in lieu of the round end corn chaffer All other optional were just things you could pick and choose things like the over-the-bin clean grain elevator, chopper, header clutch, fuel gauge, tachometer, bigger tires, hour meters, etc... This list is much more extensive.