Some of the 88 and 112 special motors were crossflows into the 90's. v4 loopers were made in 90 - 140hp flavors (beginning in 86 or 87) . . . same block, same bore and stroke. I don't know for sure but I don't even think there were porting differences. You can do a little research . . . It's probably just changing carbs, heads, and tuner will be the difference b/w 90 and 115. This is true for Merc 2.0L 135 - 150, and 2.5L 150xr6, 175 vs. 200. Sometimes just swapping carbs will give you the extra 25hp. Visit
www.screamandfly.com and you can figure out the differences in very little time.