A system for supporting a cutterbar of a crop harvesting header includes a first arm pivotably secured to the header and including a first portion configured to support the cutterbar, and a second portion including a torsion device connected to an adjustment assembly, the second portion configured to be pivotably rotatable about an axis by the adjustment assembly to selectably increase or decrease a force appliable to the first portion in order to raise or lower the first portion with respect to the header. The adjustment assembly includes a second arm interconnecting the torsion device and a first adjustment device having a first segment, the first adjustment device configured to movably receive a second adjustment device. The first segment follows a predetermined path in a first or second direction with respect to the axis in response to movement of the second adjustment device with respect to the first adjustment device.