A system is provided for controlling a line speed of a conveyor belt of a conveyor system during product changeovers in a wallboard production line. A central control module controls operation of a position sensor and a database. The position sensor is located on top of a conveyor table for providing positional information of a slurry head formed in front of a forming plate of the conveyor system. A position detection module receives a position signal from the position sensor, and determines whether the slurry head is located within a predetermined distance relative to the position sensor based on the position signal. A speed adjustment module regulates the line speed of the conveyor belt based on the position signal.