Trying to install some headers and one of the bolts broke off on the passenger side header and one nut came off okay but the one nut that's hardest to reach facing the engine is stripped and I have been going at it with Liquid Wrench and Irwin tool but no luck. So I have the new drivers side header installed but wondering if I should cut off the nut and bolt or try to protect the bolt and shave off the nut.

The bolts look like they are welded into the cat. Can anyone confirm that these cat bolts in the picture below can come out with force or if they are welded in permanently?

 

Good news is that I freed the stripped nut with the Irwin tool after hammering it over the stripped nut and cutting into the bolt to get some grip...

Bad news is that I have 1 bolt broken on the cat side so we will see how it drives with only 2 nuts of the 3 on. Tried to hammer out the broken bolt but it looks like it's welded in the cat.

Might have to pony up for some high flow cats so pricey at $2,000 for a set?

 

I had the same problem....resolved by grinding the bolt/stud and replacing with a nut and bolt. I believe the factory is pressed in.

 

this is the tool for broken header bolts . http://www.stomskiracing.com/products.php?id=61