A linkage assembly for a multiple level stack mold molding machine having a fixed platen, a movable platen, a plurality of carriage assemblies. The linkage assembly includes an arm on each carriage assembly pivotally connected to a central pivot point on one of the carriage assemblies. An arm also extends between the fixed platen and an end of one of the arms on a carriage assembly. Another arm extends between the movable platen and an end of another of the arms on another of the carriage assemblies. A pair of arms extend between each adjacent carriage assembly, each one of the pair of arms extends from an end of an arm of one carriage assembly to a central pivot point on an adjacent carriage assembly. Each arm of the pair of arms is shaped to extend around a periphery portion of a mold opening to enable full access to the core and cavity plates.