I have a '07 f150 stx with dual pipes, but it's a v6, so doesn't sound that great at high RPM's, a few of my friends have the same set ups on their trucks, but a few have cut their cats out, or gutted them and I like the sound of it. We don't have any vehicle suspections where I live, so I was thinking about at least gutting my cats. I've heard about just cutting the back 2, is that just for the noise reduction? Any tips on what I should? Also thinking of newer pipes and just a new setup, any help would be appreciated!

 

You can, but you will need O2 eliminiators for the rear two sensors to avoid a check engine light.

 

Probably a single, large diameter 'cat-back' system will be best for the 4.2. A V6 can never sound like the V8 because it doesn't have the 'throb' which is induced by the firing order. Plus, the truck won't run right without the O2 sensor in the catalytic converter. You might also consider an aftermarket low-restriction air filter, either with no housing or with an enlarged cold-air pickup. The stock system has a small-diameter hole into the fender area for air pickup. The idea is less restriction on both the intake and exhaust. You'll use more air, more fuel and should pick up a small amount of power and more noise. You might want to clean your MAF sensor in the big air tube behind the air filter housing.