Exhaust flange stud/nut removal repair

I have a question on my 95' 5.7 130K. I'm thinking of putting in a new cat ad 'y' pipe. But the exhaust flange bolts and studs are pretty rusty. My question is how easy is it to remove the studs in the manifold (incase the
studs break)? What size threads are the studs ( maybe I can run a die and clean up the threads before I back the nuts off)? Any horror stories out there?
TIA
Martin
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bolts and studs are pretty

the studs break)?

threads before I back the

PB Blaster is your friend! I had to change out the cats on my '96 K1500 and some of the bolts were really bad, I tried for awhile to get them off to no avail.. then broke out the PB Blaster and socked them real good a few times, tapped on them, etc.. and finally got them all loose.
Adair
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get out your torch if you're in a state where salt is used on the roads. You should soak them, first with some good juice for a few days, repeatedly, but I'd still keep the torch close by just in case that doesn't work. Heat the flanges to red hot all around the stud - but not the stud, itself.
Then try to work it out by running out a bit, then back in, then back out, etc. You may only get a turn or so before you have to reheat it again.
Don't get it too hot, or you'll be in a mess and don't get the manifold hot. You are ONLY concerned about the flange.
Same deal with the nuts beforehand, too. Only get the nut red hot and keep the heat on it, instead of on the stud, itself. Work quickly when the heat is on, but pay close attention to what you're doing under there because you don't want to fry anything you will need in the future
Snowman

bolts and studs are pretty

the studs break)?

threads before I back the

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bolts and studs are pretty

the studs break)?

threads before I back the

Heat helps, impact is better....
Yup, broke a cross-threaded (at the factory) nut off in a 2.5l block. I did a very sophisticated fix - I left it that way.
tick-tick-tick-tick
~KJ~
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