A row unit for a corn header has a gearbox with a cast body and first and second rotatable shafts and first and second openings. The first and second shafts extend out respectively from the first and second openings. The row unit also has first and second rotatable stalk rolls arranged fore and aft, the stalk rolls being coupled to the first and second shafts at the aft end and coupled on the fore end to first and second cast supports. The first and second cast supports are secured to a frame of the row unit. Formed from casting the first and second cast supports are respective first and second protrusions, wherein the first and second protrusions include respective first and second knife edges, the first and second knife edges located adjacent the respective first and second stalk rolls.
