We are trying to change a hub on a Campy Zonda wheel, 07, from a
Shimano freehub to Campy.
We have a Campy hub from a different Campy wheel (also supposedly 07)
but the mechanic said that it will not fit due to being a different
diameter. He said that it's a 9s hub, not 10s, and that the two bubs
\bodies are not compatible. I believe he's rather full of it,
especially since the new cassette body comes from a new Campy wheel,
not one that's 5+ years old.

Is there an experienced Campy mechanic in the house who can shed some
light on this? Peter? Anyone?
Thanks in advance.