The concern is safety. Hp limits are pretty well thought through by the US Coast Guard. And motor weights have nothing to do with it. The thrust of a higher hp motor can overwelm the stability of a boat. At the very least you will get wet, maybe seriously hurt.
And too much horsepower is not just dangerous, but wasteful. Higher displacement motors burn more fuel, even at rest.
That said, you may be fine. I suppose there may be models of scanoe that I've not seen, maybe wider and more stable. The ones I have seen were not true planing hulls. Not for nothing. Just out of curiousity, what is your transom width?
I wish you well. Use caution when testing out your new configuration.
