Re: 1992 150 vs 1988 85 hp
By three ram I suspect you mean the center trim cylinder with a pentagon shaped cap, a port side shock absorber, and a starboard side tilt cylinder.
If the transom clamps are the same, yes it will fit. BUT BE CAREFUL and question BEFORE you buy: Many times they sell the complete unit because the trim cylinder assembly is corroded onto the lower shaft. It will function and tilt, BUT: It will not pivot freely and can not be disassembled. Be especially wary if it was from a salt water engine.