Robert Loeffler, proprietor of Roberts Musical Restorations in
Deland, Florida, offers reproduction Wurlitzer unit valve blocks
for sale.  The internal valve in the block is made of leather and
is adjustable like the originals, he says.  Visit

 http://www.robertsmusicalrestorations.com/
 http://www.robertsmusicalrestorations.com/products/Wurlitzer%20Valve-detail-5.htm

Or you can build your own unit valves using plans compiled by Bob
Humes and originally posted at the Yahoo Wurlitzer 105 Group site.
The author notes that although the original objective was to make
them as close to the original Wurlitzer design as possible, there are
a number of changes made from the original Wurlitzer valves.  Visit

  http://mmd.foxtail.com/Tech/humes_UnitValve.html

Robbie Rhodes
Mechanical Music Digest