I just went looking, the first XW8 built at Acacia Ridge (in 1973) had engine number QU00002, so if this van is a 1972 Acacia Ridge assembly plant build it should have QU00001. However the fly in that ointment is there is a single HQ sedan assembled at Acacia Ridge in 1971 with a code showing it as a 350 (but no number recorded). Innuendo, is this one CHQ3x538B? If it is it should have a U engine code on the VIN plate.