A65 engine number ??

[Oval57]

Hi just bought a job lot of A65 bits, two sets of engine cases, one is 1966 the other is I think 1967. ? It has a rather long number compared to my other A65s
A65T A 1 30850 Y
So I am assuming it is an A65 Thunderbolt of 1967 era !
Not sure why the 1 is so pronounced in the stamping !
I would think the 30850 is the production number ?
The Y I have read many things about this , does anyone know the real story ?
Cheers Roger

[Big Phil]

Hi Roger,
          This article might be of interest to you concerning the "Y" suffix

https://www.jockeyjournal.com/threads/why-the-y.91975/

Regards
Phil