A header (102) for an agricultural harvester (100) comprising a frame (104), a cutter bar (106), a draper belt and a cutter bar support sub-assembly connected to the frame is disclosed. The cutter bar support sub-assembly generally includes a draper support sub-assembly (200A,200B) and a support arm subassembly. The draper support sub-assembly is pivotably connected to the support arm sub-assembly and pivotable about a longitudinal axis of the support arm sub-assembly. The draper support sub-assembly includes a first draper support (608) that includes a curved surface engaging the draper belt and a cutter bar mount (606) supporting the cutter bar. The support arm sub assembly includes a support member connected to the frame.