Hy reidy, welcome, there has been a long relationship between Canada and Australia as far as the supply of parts and vehicles in the GM family. In Canada there were Chevrolet trucks up to two ton capacity, above that capacity were Canadian Chevrolet Maple Leaf trucks of two and a half and three ton capacity, these trucks existed pre and post world war two. There were also trucks referred to as "Canadian Military Pattern" these trucks were quite different than the civilian trucks. The Maple Leaf trucks of two and a half ton capacity were powered by the Chevrolet engine of the time, the three ton Maple Leaf trucks were powered by the GMC engine of the time. All the two and a half and three ton Maple Leaf trucks I have seen have had five or six stud Motor wheels on them. It is almost impossible to say what you have there without seeing lots of pictures of the truck and its serial number plates, Holden numbers do not seem to correlate to Canadian GM numbers so you may have to find a Holden expert to help you identify what you actually have. The truck is yours to do with what you wish, but my vote is to preserve what you have for its rarity, good luck.
