The part you are describing sounds like the thermostat housing. I believe that any 194-292 part is interchangable; not sure about integral heads however. You may need to get a pipe plug or two depending on what the new housing comes from, but you should be able to make one work. If you know any one who has pulled a inline or pick a part yards you may be able to get one for free or very cheap. I found this one on ebay.
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=34202&item=2458186225 I know the one off the 194 in my 66 worked fine on the 292 that replaced it.
