Just so you know, American Racing Headers or Kooks both have longtube systems available that include high flow cats, and your existing cat-back will bolt right up without any modifications. Plus, they are stainless steel, should last forever. Won't even need to extend your O2 harnesses.

 

Thanks bud, will definitely check them out!!

 

I just installed Pacesetters today on my 2011 Sierra 1500. The headers themselves fit absolutely great, even with the 4WD. The instructions said to disconnect the steering shaft, but I just moved the coil pack mount and with a little wiggling, the driver side header dropped right in.

I will say this: DO NOT bolt up the headers until after you get the Y-Pipe all connected and the o2 sensors screwed in.

I don't know what the pre-2007 trucks are like underneath, but my Sierra came with 3 catalytic converters from the factory. So, I'm going to have the third one welded back in as it also maintains the OEM connection pipe to connect to the stock catback that I still have. This will also fix the massive exhaust leak caused by the connector that Pacesetter includes in the Y-pipe kit.