Well the numbers and letters don't really mean a lot unfortunately on these models.What I can tell you is those particular one's started in the model 5 series 2 and through until the first model Sheerline. At the time Victa had a very huge demand for their mowers,so engines numbers were fairly random,as they were just trying to keep up with the demand.A number system seemed to have taken a back seat while this demand was happening.There is a theory that the dealers were allotted their own letter prefix and the numbers were just a serial number.However no documentation has been found to support this theory.
The other numbers would just be cast numbers possibly the numbers from the moulds as they kept updating them.
There are other number which can identify the model's and years but unfortunately not these engines.
