A harvesting head for a combine and method of operating. An attachment frame at an aft end of the head attaches with a combine feederhouse. A main frame of the head is movably connected to the attachment frame, and the main frame has a range of travel with respect to the attachment frame. A resilient float element is provided between the attachment and main frames. A flexible cutterbar on the main frame operates to cut crops. The cutterbar is supported on the main frame by a plurality of pivoting arms distributed across a width of the head. With the main frame in a nominal intermediate position within the range of travel, the plurality of pivoting arms have 10 percent or less of total available travel as upward travel and at least 90 percent of total available travel as downward travel when the head is set in the nominal position.
