No such thing. throttle control.
If you are asking from a budget standpoint where is the cutoff for power before its just wasteful, then you might hsve a valid question.
I agree with the throttle control, but a ski with too much braap is no fun in the surf. I prefer a limited setup (pipe, compression, pump and prop tuning) for my surf setup. Reliability and ride time are my top priorities when surf riding. @tightithrash could offer some advice on the matter, he could probably tell you where to draw the line on big engines in the surf.
Point Loma back in the day