[willy]

There are fellows here that know these engines well and know if the weight would be a problem motor to motor.
Just being a amateur but seeing afew things in my day I would say do not exceed the horsepower rating. Do I think the manufacturer was being slightly conservative, possibly. Do I think the hull when NEW could handle it, yes.
If you are insuring the boat you will of course make it hard to collect for any damages you suffer. Could there be other legal problems, not likely but possible.
The major reason I would say to not do it is, it is unnessasary, you may be overpowering a old transom, you be be adding weight to an undesirable if not downright unsafe level.
The question in my mind at least is why?
JMHO