Aussie 47 mercury

[rotorwrench]

I would braze that with oxy/acetylene and carefully contour it back down to level. If it warps during the process, it would need the deck faced enough to straighten it back flat. It can be welded too but the block will have to be pre-heated & carefully cooled back down during the process. In either case, it may need the deck surfaced a bit. The main thing is that the outer edge of the head gasket will need to seal against a wider surface than what's left there now.