Thanks very much for your quick response!

Here's all my contact info...

Robin Glennie
12 Dupont Street West, apt 204
Waterloo, Ontario, Canada
N2L2X6

Home 1-519-746-5140
Cell    1-519-589-1148

In disassembling the pump today I noticed the pressure plate and end plate were scored - I think too deeply to machine smooth without destroying the ring seal groove. I know those score marks adversly affect pressure, but I'm not sure how much.
Given this, if you think a cartridge kit won't be sufficient, I could try to obtain a used pump as well (or, if it's cartridge set is ok, instead). A fellow on the Cockshutt site named "Marty" mentioned he had a couple kicking around - I sent him the info as well, just curious to see if one of them is a match.

 - Robin