[tsubaki]

I'll have to check the years but basically the 4cly 90hp Rudes can be improved to 140hp easily with the parts. The kicker is the parts, so many people have opted to do this that they are in high demand and rare. I got them to do one and ain't ready to share yet, only got one shot and they are real iffy as to the condition.
Basically change (or drill out the jets) the carbs and the reed plates.