Broken exhaust manifold bolt in a 5.3 going into an OBS

I have my 5.3 on an engine stand and I am going thru it, changing seals and what not. I bought this engine used from someone and it had a broken exhaust manifold bolt on the drivers rear. I removed all the other bolt after having them soak in PB blaster. I soaked this broken bolt as well. I drilled the middle of the bolt perfectly to install an extractor bit. Unfortunately the drill bit broke inside !! Its a Craftsman #1 carbon alloy extractor bit with reverse blades. I should have made the hole larger and put in a larger bit but now how can I take care of this? I have tried a cobalt and a titanium drill bit with no results. I assume I will have to rethread the hole or heli coil it if I can get the old bolt out. I was even thinking of making a custom bracket to bolt on the rear of the head (Pics below). My last option would be to remove the head and take it to a machine shop. I read on the net that I can use a carbide drill bit ? Any info would be appreciated even if it a backyard fix that some knows about !! Please help !!

http://i1323.photobucket.com/albums/...pse5f92596.jpg

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Weld a nut to it and back it out with a wrench or socket

just try and weld a bolt to it and extract it, it dont seem like it would work for that long

thanks for the reply. Unfortunately, I do not have a welder. I will see if one of my buddies have one I can borrow. Or put the engine in my old man's truck and take it to a body or metal shop that has one.

Also, the bolt in in kind of deep with all the drilling that was done. U think welding a bolt head on there will still work?

Pull the head, take it to a machine shop.

At this point machine shop is probably gonna be the best option.

Im gonna have to try the welding trick as I too have a busted bolt in one of my heads.

I have remove many bolts by welding a nut on just did the same process on my 5.3 all I use is a little cheap 110 flux cord welder and a nut with an opening about the size of the bolt. Crank up the heat and weld away fill the nut then grab a wrench right away and slowly turn back and forth. if it moves even a little shoot a little on blast in there and the heat draws it into the threads works like a champ.

Thanks again for the replies. This is how the bolt looks like in the head. Am I still going to be able to weld a bolt head to it? The heat from the welded will not hurt the aluminum head?

http://i1323.photobucket.com/albums/...psad7d4b8d.jpg