Hi Willy. In all probability it has bent the valves, I have yet to find that particular engine not suffer some damage. In a lot of cases it has done even more damage, the common one was to break the camshaft in two or three pieces!!! If the engine is very high mileage, then consider a replacement. The work needed to find if the engine will "go again" is costly and time consuming, and could only serve to prove that damage has been done. The upside of a replacement will be that you will know it is running, and before fitting, replace the cam belt and tensioners, as this is so much easier to do out of the vehicle, plus you can check the water pump bearings and if need be replace the pump. If you feel the vehicle is worth the cost. replace the pump anyway. Good Luck.
Paul
February 2008