Mike -
I've had valve overhauls on two trumpets done by
Dr. Valve (Steve Winans), and can't recommend him highly enough. I'm sure that Jim Becker and Charlie Melk would do a fine job too, but Steve is a specialist in this regard and is worth your consideration.
It's nice to hear that an old horn will be given an extension of useful life. Best of luck with this, and let us know how this turns out.