They definitely help but unfortunately it changes what I would recommend. I would replace the manifold because I am not sure you will get those out. You first need to remove the o2 sensor and then the shield around the flange.
If you remove those then you will most likely have to use a torch to heat the flange up then use a hammer and push them out. You may be able to do this easier with it off the vehicle but if that were the case, I would just put a new one on.
I think you have enough threads left there that you don't need an air hammer with a punch bit but if you have one that may make it a little easier.
Hopefully that helps. Let me know if you can get this shield off that I am pointing to in this picture. If you can the o2 needs to come out just to make sure you don't damage it. Then I would give it a shot.
Image (Click to make bigger)
Saturday, August 15th, 2020 AT 7:25 PM