We had a pair in a 38 Fountain. Put 60 hrs on them. No problems. Not sure if they really are 600 hp. They are rated to protect the bravo drives they are mated to. The 38 Fountains running 525's were almost as fast on the top end. The blowers on the 600's helped with accecleration. I think the blowers topped out at 4 lbs of boost.