Originally Posted by DarrenWS6

The part # cats you would need to run are 94306, or 94106. They are both manufactured by Magnaflow Performance and are both different, 94306 is a T-304 stainless covered converter that absorbs very little sound, 94106 are natural finished stainless ( T-409 ) and absorb no sound, give a close to cat-less sound. Both available from Performance Peddler.

Originally Posted by bigdog87

There ya go.

Originally Posted by sonnycheeba4

ok, my friend kept trying to tell me it wouldn't be the same on the 4.6 as it is on the 5.4

Originally Posted by jlstang351

check sig for video of hi flow cats. I know for a fact i didnt gain all this sound from a muffler swap! My 02's are mounted inside the cat, same way as factory piece. I went to a shop that told me the same thing about not being any louder. He also argued with me about having 2 cats under my truck. He insisted they all had 4

Originally Posted by jakek88

ur truck sounds awsome!!!!!

so what did you do about the o2 sensors being mounted inside the factory cats? did u just mount them after the high flows?

Originally Posted by jlstang351

The shop mounted them inside the cat right before the screen. I went to Darrenws6 for all my questions and he recommended the 94106 cats. I will try to get pics of 02 sensor tomorrow.

Originally Posted by jlstang351

The shop mounted them inside the cat right before the screen. I went to Darrenws6 for all my questions and he recommended the 94106 cats. I will try to get pics of 02 sensor tomorrow.

Originally Posted by bigdog87

I think that guy is a tool. The stock cats are pretty restrictive, if you got Magnaflow Hi flows, they would make it much louder. All that has to be done to not get a CEL is to have the 02 sensor mounted after the catalytic converter.

Originally Posted by jakek88

is there anyone who has done this? mounted the o2 sensors after the cats?