Originally Posted by
D1andonlyDman
Why would it be hard to upgrade a road bike from the 1980s? You can certainly get 126mm freewheel-type wheels. You can get old stems without difficulty, also friction shifting gearing components.
Yes you can get old parts, but it's
a lot easier to buy part which are current OTS, at the end of it, until the OP comes back with a
much more detailed description of what they are working with, and their experience, only generalizations can be given