A system for modifying a row unit of a harvesting head, the system including at least one cutting disk, a right angle gear set configured for being drivingly connected to the cutting disk, and a drive shaft between a row unit gear box and the right angle gear set. The system may drive two counter-rotating cutting disks that can be positioned either at near the rear or the front of the row unit. A method for modifying the row unit includes removing existing stalk rolls and housings, installing a cover plate over a gearbox to which the housings were mounted, removing existing trash knives, drilling holes in the row unit frame for mounting the cutting disks, installing the cutting disks.