Slant 6 Block Crack

Weld it and run it. Either drill the ends and grind it out, tig it up with stainless, keensert it and move on.

Or bust it out, fill the entire lug with weld, and drill and tap it. If it just holds the alternator the load is minimal and it's probably cracked from an impact or stupidity. It doesn't see compression, oil pressure, or coolant system pressure. You could silicone it to hold the oil in if you didn't need the alternator.

If it's where I think it is. I'm not super familiar with slant 6's like some on this board.