Thanks Paul for your help in locating that information...It's a C model. Sometime in the late 70's to early 80's the Boating Industry of America (BIA) appealed to all outboard manufacturers to adopt the OMC bolt pattern as the standard for all outboard mounting brackets.Most did, but others didn't. We used to refer to this as the "BIA standard" probably for lack of a better term. But even today some still do not subscribe to that old OMC pattern, so a "standard" it certainly isn't. Sorry for the late response, been away for a bit. Thanks again for your help.