A system and apparatus for controlling height of a header of a work machine such as an agricultural windrowing machine or a harvesting machine, which includes height control cylinders jointly or individually operable for raising or lowering the opposite ends of a header to achieve a desired overall height or angle of tilt in relation to the surface of a field or pasture to be cut, which allow the header to be raised, and lowered to the previously selected cut height, without changing the lengths of the cylinders, so as to be usable in combination with an optional header lift and/or float system, and including a flow divider capability which increases accuracy of height control, having particular utility for more precisely controlling the heights of the ends of the header, especially when subjected to uneven dynamic loading conditions, such as during rapid spin turns and the like.