Help with Engine Block Bracket Mount

Somewhere in the life of this freebie Big Block Ford, a farmer welded a square nut over the mounting for the alternator bracket on the block because it was stripped and broken-out. I knocked the nut off to see how bad it was. Any ideas of how to fix this?

This is for a classroom project in my Auto tech class. I have the kids researching ideas as well...

 

I'll usually drill and tap for pipe thread and install a solid square head steel pipe plug with red Loctite. Then cut flush and drill/tap for proper size threads.

 

Drill, tap, insert solid core bolt, heat it then shrink it like a sleeve in a block to insure its in there then you have a pretty good surface to do whatever you want with. Or loctite works good too if off setting the new hole with the old hole.