Mercruiser engine serial number question
 

I have a 1985 Sea Ray with a 170 engine, and the serial number on it
shows A495112. All of the schematics I can find online show that a
1985-6 engine serial number should be 6916779 and up. There is an
engine that should have a serial number between 0A331455 thru 0B527954,
but it's a 185, not a 170. Anyone have any ideas on how to be
absolutely sure you get the right part for the engine? Thx