So as not to run out of questions, I bought a 1977 18' Sea Ray, it is a fixer upper, I not know what model, the (HIN) is : SER8516Mo277 - 16710097-7. The motor (inboard) in a straight 165 HP 6 cyl. GM, the outboard power tilt, and trim, lower unit is Mercruiser. I'm going to replace the seats...