Rounded downpipe to resonator nuts even after pb blaster

[Lbeau95]

Hi there, was trying to install my cat back and have completely rounded the two nuts on the studs connecting the downpipe to the resonator even after soaking with pb blaster . What is my best option here ? Grind off studs and use new bolts ? Will the studs come out etc....
Thankyou!

 

[green_henry]

Is there enough room to use a vice-grip? Also, pb blaster sometimes needs a little help, so if you can tap the nuts lightly with a hammer, the pb blaster may have a better chance of getting into the nooks and crannies.
Good luck!

 

[D1JL]

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Dave

 

[Flaco]

Welcome ! Heat the nuts with a torch.

 

[The_Ryan]

Seconding heat. Heat+vice-grip or a bolt extractor. It was the only thing that got mine off.

 

[Gutling]

Hit them with grinder. Took my hour of frustration into 2 minutes of grinding and they were gone