Abstract: A preform mold assembly for the injection molding of a multi-layer preform for use in the blow molding of container. The preform mold assembly comprises a preform mold having a gate for receiving molten plastic material. The preform mold has a cavity with longitudinal axis and defines an inner surface. A core-pin is situated within the cavity and spaced from said inner surface. A preform cavity is formed between the inner surface of the cavity and the core-pin for receiving molten plastic from the gate. A threadsplit portion is situated within the cavity at a location remote from said gate. The inner surface of the cavity defines a plurality of flutes formed generally parallel to the cavity longitudinal axis and extend longitudinally along the inner surface of the mold to the threadsplit portion.