Originally Posted by Karl

Im affraid the head is essentially scrap. You cannot successfully repair that type of crack in the chamber.

Even if the crack does not currently pass through to the water jacket (i.e. it passes a pressure test) it will only be a matter of time until it does.

I deal with these issues on a weekly basis as we repair heads that for example have dropped a valve, but when you have a cracked chamber it is a futile effort. Strip it for its parts (i.e. valves etc) and replace the head casting with an uncracked item.