A crop harvesting header having a frame mounted on a propulsion vehicle has a cutter bar carrying a sickle knife and a draper transport. The draper is guided at its front edge by a longitudinally extending rail mounted on the frame for movement therewith. The cutter bar is mounted on the frame at spaced positions by spring blades attached to a fixed beam at the rear which allow up and down flexing movement of the cutter bar relative to the draper engagement member. At the center discharge the cutter bar is carried on shorter blades which are carried on a beam in front of the front draper roller. The small amount of flexing of the cutter bar combines with a balanced three piece header frame to provide effective ground following.