I am a cheap *** and want to use a universal cat when I replace mine. Problem is my old cat has the o2 bung on the cat. Would it mess anything up to weld in a new bung just a few inches downstream in the outlet pipe? If I do do I need to get an actual bung, or will a nut that fits the O2 work?

 

i just replaced the cat on my 96 and i bought a 55$ dyno max cat, 3$ weld in o2 bung and 12$ or 4 feet of 2.5" pipe, 30$ raptor welded muffler and had an ehaust shop build me a tail pipe for 35$. i did all the labor and welding myself all 2.5". sounds awesome and came out clean!!! I could not find a nut that the o2 sensor would fit but the pipe i took off had a nut welded on for the bung and it looked absolutely horrible.... i don't know how it didn't leak!!

 

Just buy a spark plug non-fowler and weld it into the pipe where ever you choose.

 

the magnaflow universal cats come with bungs...specific part number denotes at no bung / at entry / mid cat /at exit location. available at most parts houses ( aroudn ehre anyway)