if you can get to the crack it can be stiched using square drive cast iron pipe plugs, center punch at the end of the crack and drill and tap it with pipe thread and install a solid cast iron pipe plug take your small grinder with a cutoff wheel cut off the square drive head and grind flush with the block. then center punch the edge of the plug you last installed where it meets the crack drill, tap, install, cutoff, and grind, repete untill you have covered the lenght of the crack. each plug overlaps the last,that you can do without tearing down your engine and i used the perminate type of permatex. you can do