a system and method of cyclic injection molding a plastic material by controlling hold pressure and transferring plastic material to molding cavities of a stacked multi - parting injection molding system having desynchronized injection periods . the system includes left , left center , center , right center and right molding blocks disposed for movement with respect to each other along a common axis ; and defining a left molding cavity between the left and the left center molding blocks , a left center molding cavity between the left center and the center molding blocks , a right center molding cavity between the center and the right center molding blocks , and a right molding cavity between the right center and the right molding blocks . the left center and right center molding blocks each contain a bifurcated runner system , confining means for confining injected plastic material therein , hold pressurizing means for hold pressurizing the confined injected plastic material in the bifurcated runner system and an inlet orifice , for feeding the adjacent molding cavities . the system further includes a clamping unit for moving axially the left molding block in relation to the right molding block and providing collective axial clamping force on the left , left center , right center and right molding cavities ; a left locking system for maintaining the left and left center molding cavities in a closed position when the right center and right molding cavities in an open position ; a right locking system for maintaining the right center and right molding cavities in a closed position when the left and left center and right molding cavities in a closed position when the left and left center molding cavities are in an open position ; and an adjustable feed system encompassed by a combination of the left center and the right center molding blocks and a plasticizing system which has one or more outlet orifices .