Will the Lower Unit from a 1998 75 HP Yammie fit a 1991 C85??

[Spottail Chaser]

I am about to have to have some work done on the lower unit of my 1991 C85 Yamaha. I have found a lower unit off of a 1998 75 hp Yamaha and am curious if they are the same size. Any help with this would be appreciated. Also, is the tilt and trim unit the same on both motors. The part appears to be the same, but I was curious.

[boats.net]

According to the parts book the lower unit will not interchange. I'm not sure what the difference is. The power trim should work on the C85. Be sure to look at the relay, if the C85 has a 3 wire trim motor then the relay will also have to changed.