Head gasket issues

I hav had some leaks from the head gasket. It looks likthe head is bowed up in the middle.

I took a piece of 1/2"plate glass and stuck some 80 grit sandpaper to it. After rubbing the head on it for some 15-20 minutes I got it to be flat with slight sanding marks across the center..

I did the same thing with the engine block.