I put stainless bolts and nuts in all the flanges after the cat. They always come out.
The 3 header nuts that's on the down pipe that has one or 2 cats on depending the year. Are special single use nuts.
However, if you remove the studs and drill them out. [ because of damage or snapping off etc ] You may wish to put stainless bolts and nuts there so you can get it apart in the future if need be.
Sent from my SM-J337V using Tapatalk
__________________
7 3rd gens listed in the build thread (2 are parts mobiles)
Build Thread:
https://www.toyota-4runner.org/3rd-g...os-builds.html
Brillo's Bucket Fluid Ex changer:
https://www.toyota-4runner.org/3rd-g...ml#post3358086
Sparks Plugs Wire and Coil Information:
https://www.toyota-4runner.org/3rd-g...on-5vz-fe.html