Mr. Colerich informed us yesterday:
> <<Shimano introduced their first Dura-Ace "gruppo" in 1974. Around 1975
> they put together a hodgepodge 600 "gruppo" made up of differing
> qualities of components badged with the 600 logo. By 1976 it became a
> more cohesive product line.>>
>
I have one of those earliest of Dura Ace catalogs and the only '600'
components contained therein were two rear derailleurs; a standard and a GS model.
They had very prominent "New" wording on the photo. They looked a
little like the Crane models but quite a bit "clunkier." There was no other
reference to any '600' model components at that time.
Cheers,
Chuck Brooks
Malta, NY NEUSA