Headers/manifolds 4.0

Who has changed out stock manifolds with headers? I'm looking for something to keep the cats, and that won't turn a check engine light on?

 

I’ve changed the headers to long tubes. You can get short tubes that will keep the cats. However if you don’t want to, you can get O2 sensor sims that tell your ECU you still have cats.

URD (URDusa.com) has a few options for headers and they sell the O2 sims as well.

 

I've seen a couple of posts about these (Magnaflow) but nothing to say anyone has installed them or is happy with them. I bought a set yesterday because the cat's are included and I'm hoping these bolt up and require little to no fabrication. I want to stick with the shorty header for the torque and keep the cat's to avoid throwing a code. These and the fuel pump/filter and radiator upgrade are in preparation for the blower installation...