A locking mechanism for an agricultural header includes a rod configured to extend laterally along the agricultural header and a cam coupled to the rod and configured to engage a respective arm of the agricultural header. The arm is configured to support a cutter bar assembly of the agricultural header, and the arm is configured to rotate relative to a frame of the agricultural header. The rod is configured to rotate in a first direction to a first orientation to engage the cam with the arm to block rotation of the arm relative to the frame, and the rod is configured to rotate in a second direction, opposite the first direction, to a second orientation to disengage the cam from the arm to enable rotation of the arm relative to the frame.