You said that you don't know where the transmission came from. It's possible that you got your hands on a variable pitch trans, which that converter won't work properly with.
Read this and let us know if that's what you do have:
http://www.442.com/oldsfaq/oftsp.htm
Read this and let us know if that's what you do have:
http://www.442.com/oldsfaq/oftsp.htm