I believe to be a 1968 Mercruiser 160 HP straight 6 cyl. is stamped with a serial #F12176BJ at the base of the distributor. Can anyone break this Mercruiser engine number down for identification. Also can you furnish the correct tune-up specifications and the correct spark plugs for this piece of history. I can find nothing on-line and for this engine. They always show information for a newer 165 HP. Happy Sailing! - Rich