Joined: Jul 2011
Posts: 605
Likes: 11
From: Denver, CO
Bikes: 1966 Carlton, 197X MKM, 1983 Trek 620, 1988 Schwinn High Sierra, 1995 DBR Axis Ti, 1999 Waterford, 2016 DBR Release, 2017 Surly Travelers Check
Change is about 4-5mm from 27-700c.
One thing to keep in mind is some tourers in the 80s had narrower spacing between the canti posts than modern cantis or mtb cantis of the era. This makes the pads too close together (i.e. they hit the rim and can't be adjusted further out).
Only way to know on your particular model is to try them out.