A mower deck insert includes a first cutting chamber, a second cutting chamber, and a discharge passage extending adjacent to the first cutting chamber and the second cutting chamber. The first cutting chamber includes a first axial scroll extending about a first vertical axis. The first axial scroll includes a first upper surface having a first start region and a first end region. The second cutting chamber includes a second axial scroll extending about a second vertical axis. The second axial scroll includes a second upper surface having a second start region and a second end region. The first start region is vertically lower than the first end region, and the second start region is vertically lower than the second end region.