asellers23

Hey everyone, I have a 2004 5.4L 2X4 F150 and I want to put High Flows on it. It already has true dual straight pipes but its just not loud enough for me. What I'm asking is how many cats does my truck have and how many would I need to buy. Thank you.

JCT1990

It has 2 cats one coming off of each manifold

otto457

The 04-part way through 06 has four cats total, two on each side. Deleting the rears would be a good first step, then move up to high flows if it's not enough sound for you.

asellers23

So I only need to buy 2 cats?

otto457

Your truck has four stock. You can delete the rear two stock ones and see how you like the sound level. Alternatively, if you want to go to high flows directly, you will need to buy two high flows (Magnaflow 94106 or 94306 for example).

greenmudder

If you delete the rear 2 would it throw a trouble code?

otto457

^ It varies. If the front cats are doing enough it won't trip anything. If it does trip a CEL, then a non fouler/O2 mod should eliminate it. A custom programmer will also be able to turn off the rear O2's.

asellers23

so gents, what your saying is i dont really need to buy any high flows. i can just "delete" the back 2?

svs

Couple of questions?

Back two, meaning the 2 cats nearest rear end?

Also will removing these rear cats free up any hp or would this mod just give you more sound?

Thanks

otto457

Yes the two closest to the rear of the truck. Won't free up any noticeable power, this is done only for an increase in the volume.