there have been some people that have gotten over 50hp from it. you could probably get around 60-70 from it but it would be a time bomb waiting to go off
I would say that to still have a reliable rideable quad that you would be in the neigborhood of 40 horsepower...maybe a touch more. It really depends on what you are after as I have heard of 60+hp drag blasters.
The build in my signature is 34hp... I do not know if it is whp but it is a dune port w/ 3mil stroker and stock bore. I know that their is more to be had but this is what Angus recommended for my weight and riding style. I:I