Beast i would say 850/900 ( 900 high end ) if the engine has all the other stuff working right.
Just to give you a comparison. Scott Schaffiroff is known for advertising HEALTHY hp ranges on his engines....Not that i support his engines or that i would buy one..but i think comparing his HP ranges will get you in the ball park.
( for the record i am a PAR man)
on his site the 540ci ranges from 825hp to 860hp..
http://www.shafiroff.com/sportsman/540_860.asp