A system is provided for controlling a line speed of a conveyor belt [22] of a conveyor system [12] during product changeovers in a wallboard production line [14]. A central control module [40] controls operation of a position sensor [36] and a database [42]. The position sensor [36] is located on top of a conveyor table [18] for providing positional information of a slurry head [34] formed in front of a forming plate [28] of the conveyor system [12]. A position detection module [48] receives a position signal [P] from the position sensor [36], and determines whether the slurry head [34] is located within a predetermined distance relative to the position sensor [36] based on the position signal [P]. A speed adjustment module [50] regulates the line speed of the conveyor belt [22] based on the position signal [P].