Before you decide to junk that unrepairable engine block watch this...

So on a garage level repair, you just drill the crack and screw these pins in, tighten and grind flush? Do the pins need to overlap? That large scale ship repair is something else! USA!

I watched a huge 80" valve seat being ground with a grinder on a boring bar. He just set it up and started rotating the rigid jigged grinder around the valve seat. Simple yet effective