[DarrenWS6]

Originally Posted by dc_racing

Okay well im thinking of going with the 11" magnaflow with the rear converters out. I forgot to say im replacing the pipe from the headers back cause its leaking in a couple spots, so what should i do about the cats? get new ones or can i use the old? i really dont want to replace the O2 sensors if i dont need to.
Thanks.

If your cutting the rears out and running only the pre-cats, leaving the factory pre-cats should be just fine. The shop should re-locate your O2s for you to prevent a CEL. Getting a shop to do it depending on your area may be difficult,its not exactly a legal procedure, but these trucks dont need all these restrictive cats.

If you decide not to go through, and want to replace them with aftermarked hi-flow cats, I would suggest Magnaflow cats, any 94000 series, 3 that I know that will be guarantee'd to work would be part #94106., #94006, and #94306. The differences between these cats are, 94106 is a 9" length body, it will be the loudest and shortest, 94006 is the base model, 12"s long and louder than 94306. 94306 is a calmer version of 94006, Troyer Performance recommends them. I would go with the 94006s or the 94106s.