Sounds like a great project. I built up a NOS late '80s frame with NOS Triomphe/Victory group last summer. I did however use shimano 7spd cassette wheels and have no shifting issues on a 12-23. I think it will go 8 but never tried it.
what front derailleur are you using? I am doing something simiar trying to put late '80s Chorus on 09 frame but the brazeon FD does not seem to be in the correct position.
why the disc brake?
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“One morning you wake up, the girl is gone, the bikes are gone, all that's left behind is a pair of old tires and a tube of tubular glue, all squeezed out"
Sugar "Kane" Kowalczyk