lee, You need the longer cutters on the stationary part of the chopper. If yours is factory installed, you already have the longer coined (sharpened) cutters which first showed up on the 2001 models. Also, a kit was offered to allow you to raise or lower the stationary cutters from outside of the combine, the only changes since the chopper was introduced on AF combines in 1981. Be sure they are pushed up all the way up. If you want a taller cutter, I could sell you a 'Skipper Cutter Kit' which has a taller knife (sickle sections)1_2 inch taller, not sure you could still adjust from the outside w_o some modification inside. This kit will work on this style chopper all the way back to the lo Pro 915 (1974).