A mold unit has first and second parts, each with a plurality of cooperating cavity portions. The mold unit further has similarly interconnected third and fourth mold parts. An operating system moves the mold parts to change the mold unit between first and second states. The first and third mold parts meet at a fixed, first parting line to define a first plurality of mold cavities, and the second and third mold parts meet at a fixed, second parting line to define a second plurality of cavities with the mold unit in the first state. In the second state, molded products formed from the parisons can be released from their cavities.