I presume you got an answer from Simon Dinsdale? If not let me know
VOC Machine Researcher
Maybe you should speak to the Machine Registrar Simon Dinsdale. Details in the front cover of MPH. He will help you.
If it ain't broke, it's just a matter of time.
I have a 1949 Vincent Black Shadow and it had the rear frame member replaced with a 1951 shadow RC8316B. I know this is a long shot but I am trying to locate the original rear frame member (if still in existance) which will be marked RC4449B. Any help would be appreciated.