Without more info this is the best I can do. One of these should fit but you would have to know what year your outdrive is, sometimes an outdrive in the boat is from the year before or after hence a 1978 boat could have a 1977 or 1978 or 1979 outdrive as the boat maker buys the outdrives in quanity from OMC and installs them in the boats as the boats are built. If you can find the number on the outdrive then you can determine what year you have. Also you can count the mounting holes on the boot and that should help you to determine which boot that you would need. Boots are noted for being expensive.

http://www.ebay.com/sch/i.html?_trks...+boot&_sacat=0


You could also go here and join the forum and ask the experts there. Just be sure that you ask in the proper forum, it is free and very informative they may even walk you thru the replacement procedure. They have helped me on several occasions and most of them are super friendly and they live and breath boating and boat repair.

http://forums.iboats.com/forum.php

Look for this sub-forum on the above link and ask your question there, I think you will be surprised. OMC I/O & Inboard Engines & Outdrives