Broken Exhaust Manifold Studs

So, I really thought I was ready to replace the exhaust manifolds on the 2005 DC Limited we got for my son as a first truck.
We are replacing the entire front suspension, steering rack, SAIS, timing belt, cooling system, starter, cracked exhaust manifolds, etc.
We have had pretty good luck with the project until we got to the exhaust manifolds. We used a MAPP gas torch to heat each of stud/nuts prior to removing them. The two upper center studs on both sides snapped leaving about 3/8” of the stud. Most of the other studs came out with the nuts. Nothing I read said I should expect the snapped studs.
I attempted to remove the studs with a chuck style stud remover but had no luck at all.
With a bit of research, it looked like lots of people with broken studs have had good luck welding nuts to the broken studs to remove them. So we tried that and even though we were getting great penetration, the studs just shear off to the point that they ultimately end up flush with the head surface.
I feel like the only choice we have is to remove the heads to have the studs removed so that we don’t damage the heads.
Has anyone had this hard of a time with exhaust manifold studs?

 

yes….VERY difficult time!

MAPP gas ain’t hot enough. You needed an oxy acetylene torch to get it hot enough. There’s still a chance you can still back it out by welding a nut on it (even though the broken stud is flush with the head), but you’ll want to get that stud glowing orange, then use a 220v welder (110v won’t get hot enough, quick enough) so weld a nut on it. Buy a handful of nuts. Something like 10~15 of them so that you can perform multiple attempts.

If welding a nut doesn’t work, then it’s time to buy a few high quality titanium coated drill bits. If you have a high skill level with drilling, then Bob’s your uncle. Then chase out the rest of the threads with a tap.


NOTE: all of this is easily said than done, but those are the options.

 

I’ve seen videos of people building up the welds, even below the surface of the head and it allows them to pull out the broken studs. It looks as though the threads are not damaged during this process but I worry that my skill level is not overcoming the level of risk…
I won’t be drilling in this confined space, too much risk.