Broken off main cap bolt

I have a problem,tore down a 1995 360 yesterday and broke a #2 main cap bolt.A friend of mine bought and I told him not to buy it from the guy he bought it from.I dealt with this same guy he bought it from before,a shady POS and screwed me on a part.He has plans to rebuild it.Tearing it down,had a problem with this rod cap bolt removing it.My good IR 1/2 impact would not touch it including breaking two of my good Snap On breaker bars.Had to get my 3/4 breaker bar out to break it loose and it broke.It was worked on before and I am thinking the previous person crossthreaded it putting it together.I can't get a nut welded on it,3/4 down is where it's broke off in the block.Probally a hardened bolt and probally a pain to drill.Suggestions?I know where there is a good block and told him this

There are two ways this can happen. Ive seen both. First, could've been cross threaded, if thats the case, its galled up in the threads and will never come out unless its machined out. There is no way to save the threads. Second, they installed it without any lubrication, this can cause the two metals to "cold weld". I use quotations as its not a true cold welding, but enough to cause microscopic welds that break and gall up when removed, that will never come out either.

Basically, you're looking at taking the block to a machine shop and having them drill it out and rethread the hole in the next closest size of the opposing standard, or scrapping the block.

It was a mess and not put together right.Machine shop did get the broken bolt out,drilled it out with a carbide drill bit and retapped the bolt hole.The block was no good,magna fluxed it and found a huge crack in the lifter valley.Did get the other block and this block is a good one.