Adjustable cutterbar travel range for a flexible cutterbar header

A harvesting machine includes a harvesting header with a header frame, a cutterbar assembly attached to the header frame along the length thereof and configured to cut a crop, and a draper assembly positioned behind the cutterbar assembly and operable to receive severed crop material from the cutterbar assembly. The draper assembly includes a center draper that delivers crop material to a feeder house of the harvesting machine and oppositely spaced side drapers that deliver crop material to the center draper. The harvesting header is operable to flex and thereby follow an uneven terrain.