prop shaft seal part no.

[thunderroad]

I need a couple of prop shaft seals for my 160. The seals that came out were C/R 504652 but this number isn't in any cross reference I can find. I'm about an hour and a half from any Mercruiser dealer and would like to find them locally (NAPA,CarQuest or the like) Is this possible or are these unique to mercruiser? The best I can tell they are 1.1875 inside and 1.6875 outside. Anyone have a different number or know of a good cross reference source?<br />thanks