In Utah if you can get your hands on the original title (see picture) the engine number and the serial plate number were both used.
http://www.flickr.com/photos/advance-design_parts_co/9035376513/in/set-72157631867396207
I was so pleased to find the original instead of relinquishing it for new I applied for a replacement title and kept it! My 216 had a 3' long crack in the block so it was not salvageable now running a 54' 235.