Yes well as you said it is a good one to start with and learn from.As far as your numbers goes unfortunately I haven't found a lot of info about the series 80's engines as all the previous numbers systems that Victa used seem to go out the window.
They relied more on the Victa code and model numbers.Which were stickers and could be easily changed.From you first picture that is just a part number for the upper crankcase.
The second number (and this is only from my own observation,from mowers that I have and seen over the years) the 3 is a model number (Of which I have no idea what model) and the 9 means it was build in 1979 and sold as a series 80.The other numbers I have no idea at all most likely just a serial number.I really don't know anything more about those numbers.As I said they changed to using the Victacode and model numbers more than identifying by engine numbers.
