a question for merc people or anyone else

[lathehand]

I just bought a merc 1986 90hp inline 6 and it happend to have the original installation manual and it also covers the 75 and 115 hp engins.while looking at the prop slection I noticed the WOT on the 90 is only 4500-5000 rpm the others with the same prop and weight boat is 5000-5500 rpm.I did some online searching and discovered the only diffrences in the internal parts of this engins is the carb jets.Next I looked up in my sirvice manual and noticed there were diffrences in the timeing.Now with this being said if I were to rejet and retime my 90 I should be able to push it it up to 115 hp or am I just spitting in the wind.Has anyone out there ever atempted this and what was the outcome.I posted this in a mercury forum but got no replies.Maybe they don't want the truth to sneek out on how they make one motor and make suddle changes to it and call it something else.