A harvesting header having a flexible cutterbar assembly utilizes draper belts behind the cutterbar assembly to gently consolidate the severed crop materials and deliver them to a point of discharge and delivery, such as to the feederhouse of a combine harvester. The header includes laterally spaced support arms. The support arms are attached to the flexible cutterbar assembly and pivotally supported adjacent rear ends thereof for swinging movement about a laterally extending axis.