First HZ vans were July 1977 and this included Sandmans, but volume production didn't start until near the end of the first week of September 1977 although there are a fair few HZ's (not necessarily vans or commercials) built starting in the last weeks of August 1977. The last HX's were finished in the first 2 weeks of September 1977 but most were finished by the end of the first week, many of these are 8/77 plated though probably as there were ADR revisions associated with the 1978 model year starting on 1/9/77.