At worst you might get an exhaust manifold from the junkyard Whis would be a great opportunity to dress it up real pretty meanwhile it'd be easier to take off the junk yard o2 sensor and pop in your new one. Don't let o2 sensor replacement go too long in the future. From what I understand though you want the manifold to be dead cold to avoid expansion of the threads. If you stripped the threads use a vice grip and FORCE it off. I like the junkyard manifold idea best.