clay, there are 4 cats on your truck. there are 2 cats on the "y pipe" and 2 cats on the main exhaust. between the 2 cats on the main pipe there is an O2 censor plugged into the pipe, if you take off the cat AFTER the O2 censor (the VERY LAST FARTHEST BACK CAT) you will NOT throw a code, because there is nothing after this cat for the engine to read, therefore it is pretty much just there for now reason, i promise you wont throw a code by removing the last cat closest to the muffler, but if you still have doubts, ask a performance shop.