Gidday Blended and all,
The engine to me looks as though someone has replaced the lower crankcase with a 1966 case ,the
top half has the front mount air cleaner so that casing is 1963 to 1965 but the lower casing is 1966
and the 1966 Victa 125cc doesn't have a front mount air filter.
My Corvette engine numbers are 1966 ( 666 )
1967 (667 )
1968 (668 )
1969 (669 )
6 at the start is the code for Corvette then the second two digits are the year of build.
Image below 1966 Corvette.
https://www.outdoorking-forum.com.au/forum/ubbthreads.php/topics/84621/victa-news-cuttings-january-1966.htmlCheers
Max.