Thanks Greg for your order of your F.A.S.T. head and parts. Sorry it was so busy, that is just a normal day around here. I think we had 6-7 calls just while on the phone with you so thanks for your patience. HP will depend alot on your porting but i would think at your altitude you should be in the 55-60 hp range. Should be able to hang with most 4 strokes w/pipes but with much more than that and these newer 4 strokes really run well. Enjoy!