02 sensor troubles

hey i was putting in an o2 sensor into my 94 supreme with the 3100 v6 in it and the threading in the manifold was all stripped. ANwyays, my idiot cousin thought he could just cut all the threading off the sensor and JB weld it into place. That worked for about a day, and i don't know another way to get it to stay other than threads (its too tight a place to tack-weld or to make a bracket.) So i was thinking, could I cut the o2 sensor wires, put extensions between the to make the wires longer, and install the sensor say, right before the cat? just wondering cause he vioded the warrenty on it and i dont wanna buy another at 54 bucks a pop.

anyone have any ideas to if it would work?