Fietsbob, I had a 6 cog in there on the campy low flange, nominal spacing 120mm, and it worked fine.

Sheldon, of ever honored memory, gives 120 as allowing 5 or "Ultra-6" cogs 126 as allowing 6 and 7 speed cogs. (His crib sheet is here). I guess I have an ultra 6.

Right now, I have a 1999 Lemond Zurich in 853, that was spaced to 126. I bumped it to 130, and made sure it's aligned. I also had to open up the dropout, whi]ch appeared to be sized for a 9mm axle instead of modern 10mm axles. If that rides as nice as I think it will, well, then "I can't afford to go chasing nostalgia" as a local bike shop service manager opined (about his own situation).

That said, if I could find a 23-1/2" or 24" Paramount frame in 531, then perhaps I could put together something both beautifully vintage yet ridable. I weigh 240, am older now, and have some climbs on all the rides around my house, and so getting a rear 28 tooth cog on a 7 speed hub would be a good idea.