Originally Posted by
harrism
This exactly. I haven't removed the housing yet, but from everything I understand, modern housing won't work.
That is not correct. Modern housing will work fine. Main issue is that it might look stupid. Also, modern shift housing must use ferrules (end caps), and there is a slight possibility you may have some trouble fitting it into whatever cable stops are on your bike.
FWIW there didn't used to be separate brake and shifter housing, as shocking as that may be. It was the same. Really any coiled housing will work.
Modern shift housing was introduced in the mid 80s, and is made with linear strands of wire that are parallel to the cable, so that it compresses less.
Dry lube is not correct for vintage
unlined cable housings for brakes or shifters. They should be greased. Very heavy oil is ok if that's your preference.