Abstract: Apparatus for testing air flow through a dual-stage blowhead that includes an adapter block with a blowhead cup for releasably receiving a dual-stage blowhead. The adapter block has a first block passage for feeding test air to a first inlet of the blowhead for conducting blow air to a parison, and a second block passage for feeding test air to a second inlet of the blowhead separate from the first inlet for conducting finish cooling air. Air is directed from a common source separately to the first and second block passages, and air flow is measured in each path. When air flow through the finish cooling air path is less than a predetermined threshold, or less than a predetermined ratio with respect to the final blow air, this may indicate a need to redrill or otherwise rework the finish cooling passages in the dual-stage blowhead.