im trying to put them back on. now i have the sensor still on there. what happened was it wouldnt come off when i took the headers off. this was done in a shop with a sensor tool and it stripped it and then we heat torched it and it woulddnt loosen. any ideas to get it off. cut and pry? idk. i have a sensor for it just need to get this one off first. please help

 

Well, if the old one is junk you don't have to worry about damaging it.

I would have left the manifold on the engine, that will keep in steady so it won't move around.
It sounds like someone hacked at it, they normally aren't that hard to remove, even if it takes some effort, they don't tend to strip if you have the right tool and you have it squarely on the sensor. Heat would be my first suggestion, it has to be loosened while it's hot though. What did you use for heat? If you didn't use a real torch [Oxy Acetalyne] you probably just wasted your time.
Whacking it might jar it loose, also try tightening it and then loosening it.

It sounds like you can't get any kind of a grip on it at this point, you might have to cut/drill/torch it out.
Hard to say for sure without being there.

 

yeah im thinking il have to cut it and try to get a grip in it and try twisting. its defintly stripped. it was actually heated with a heat torch or whatever. like i said it was done in a shop so theres welding junk and all that. but it didnt budge. we treid heating the surrounding area then twisting.

 

i used lots of wd40... and vise grip pliers... it worked... but i got a new sensor tho before hand..lol

 

yeah i got a new sensor when i had taken the stock headers off. just left the old one on. but its time to put stock headers back on so i need this old one off and then i can just use the new one i already use now

 

That's part of the problem, you don't heat the surrounding area, you heat the sensor, or bolt, or whatever you're trying to loosen.