Upper Middle Petrol Head:

  For non-Aussies readers, this is a 48-215 Holden, aka an "FX," which was General Motors' first ever car to wear the Holden badge.  According to Wikipedia, the FX name was never officially used by GM but was actually an internal code to distinguish later 48-215s fitted with telescopic front shock absorbers from the earlier versions equipped with lever-arm dampers.  However, the term caught on and eventually became the model's unofficial model name for both early- and late-built examples ( https://en.wikipedia.org/wiki/Holden_48-215 , accessed 08 AUG 24). So, how did GM come up with the 48-215 designation?  According to the same source, it's actually very simple:  '48 was the car's first year of manufacture and 215 an expression of the engine's 2.15 litre cubic capacity (ibid).  That said, I do question why a US-owned and based company operating in Australia would be using litres, given that both countries were very much non-metric back then.  Moreover