a blow molding assembly for thermoplastic resins , used , for example , for the manufacture of bottles wherein parisons are heated in an oven and then transported to a mold station where they are biaxially oriented and blown . the invention is particularly concerned with a transport system operating from the oven to the molds , wherein the spacing between the various parisons being transported by means of picker means can be adjusted so that the parisons may be introduced into molds at a spacing different from the spacing of the parisons in their travel through the oven . the transport system includes means for picking off parisons from a conveyor with a predetermined spacing and means for spreading or narrowing the spacing to match the centerline - to - centerline spacing of the molds .