On Mon, 29 Jan 2007 18:34:50 -0600, Guy F. Anderson Sr.
wrote:

I need to replace the rear derailleur on my Campy Ergo 7-speed system.
I have a 2003 Chorus 10-speed derailleur. Will it work,
or do I need to pop for a 7 or 8-speed derailleur?

You don't need to pop for a 7/8 speed rear derailleur in because there
is only a mino difference in the amount of movement from the older
models to current models
http://www.ctc.org.uk/DesktopDefault.aspx?TabID=3946. I'll sell you
an 8sp Record rear derailleur in excellent condition for your Chorus
10 rear derailleur and give you some cash too.