The Ampex Mailing List and Virtual Museum is a hobby (some might say obsession) for me, Howard Sanner, the webmaster and mailing list moderator, using servers provided by Josephson Engineering.
I do not stock or sell parts for Ampexes. To get parts, contact the people and firms listed in Dave Dintenfass's Parts Sources for Ampex Buffs or subscribe to the Ampex Mailing List and troll for parts there.
Similarly, I cannot estimate the fair market value of Ampex equipment or parts. I have not been involved with Ampexes changing hands for money for so long that any opinion I gave would be meaningless at best. Searching eBay for completed auctions may let you know the price for which the same or a similar item recently changed hands. Pro Audio Marketplace, a subscription web site devoted to sale of professional audio equipment, may provide asking prices for equipment.