A crop harvesting machine with a cutter bar on a header frame has aheight control system which uses depending sensor fingers arranged in contactwiththe ground so as to measure a height of the cutter bar above the ground. Thesensorfingers are controllably retractable under actuation from an operator in thecab orautomatically in response to prescribed conditions being met. The actuatorused inretracting the sensor fingers can also be used to adjustably control groundpressure ofthe sensor fingers in the deployed position of the sensor fingers engaging theground.The header height is adjusted using laterally spaced apart hydraulic linkageswhich canbe operated at different elevations relative to one another responsive todifferent heightsignals relating height of opposing ends of the header frame relative to theground toalso control tilt of the header relative to the harvester frame.
