after my 502 was destroyed by a dealer i started to rebuild it this winter.

engine is bored and honed, new keith bleck peformance(dome) pistons (cr 10.4)
this compression is no problem because of the higher octane in the netherlands 95
new bearings

cast iron heads , new valves.
distribution gear drive

high volume oil pump

compcams extreme marine cam

http://www.compcams.com/Company/CC/c...?csid=404&sb=2

can someone give me an indication what hp to expect?

Not enough info .......what kind of induction? Intake, carb, E.F.I? ....what are you running for exhaust? What size valves are you running?

more info ..Cam specs?,..but beyond that,, if you aren't sure what you are getting in to ,in my opinion you should either follow a proven combination or just un -destroy what you have ....put it back stock ...You can end up spending money and going backwards in a hurry.
(EDIT)
didn't mean to come off as a dic .A mild cam with that compression and the fuel to support it will give you some power? What is specs on cam ...or part #.To get anything meaningful you needs to address all parts from spark arrester to exhaust tips as a happy combination ..induction is only as good as it's weakest link. What heads you got ...casting#?
And with a hi-volume pump you'd better have an oversize pan