Where is the crack, and is it in a place that would affect the structural capability of the cam cap?
I've got a motorcycle engine with a cracked cam bearing cap and I've put 25,000+ km on the engine with the crack plus who knows how long the previous owner had it like that. The crack is not in a critical place. Same situation with the cam caps being machined together with the head.
If the crack is directly over the bearing surface and all the way across, that's bad. But still ... you can scrap the head now, or you can run it the way it is and it might fail tomorrow, or never fail for the next 200,000 km.