Found another engine on Ebay. This one is a beautiful old engine once used to run a belt-pully system to power machine shop tools. Due to the arrangement with the double wheels I can easily picture it in a good sized sidewheeler. (maybe 50 feet or larger LOA?) It's a pretty big engine.
http://cgi.ebay.com/ebaymotors/Live-ste ... 20b5b05214