Im having my stock cats taking off and having high flows put on. Will it make my truck louder? I have a 2007 f150 5.4l if it matters.

 

......yeah

 

By a noticeable margin yes. Just make sure they are installed correctly by removing the downpipes, and the O2s get mounted after the cats if you do not chose the O2 mount 94136 cats. A few folks lately have had troubles with their hi-flows, John ( truck_guy24 ) to be one of them. Which has possibly eliminated my desire for them. However Dave here is still happy and trouble free with his.

 

well I'm getting catco cats, so I'm not sure what the muffler shop is gonna do with the O2 sensors but ill ask, And I'm not really concerned with loudest it was just a thought, One of my cats is clogged so ima go ahead and replace both. thanks guys!

 

I put pacesetter headers on mine. I removed all 4 and put 2 12in cherry bomb glass packs then lead them in 2 full sized glass packs with 3in pipes in front of the rear tires. It is loud when you have a lead foot but sounds really good and is moderate for cruising on interstate.

 

I have the 94136 magnaflow cats with the 02 bung in them. No problems here after 5 months and they sound awesome. Just be aware that I LOVE loud aggressive exhausts and you may not like it. Last week I set off a car alarm in a parking garage on campus....it was awesome.

 

I went with the catco and like you dave06ford, I love loud, I like it when I crank up and it scares everyone and sets of the 3 cars park around me haha

 

yeah and im not sure if i need long tubes because that would be so insanely loud but the performance gains would justify it lol....no expendable income at the moment

 

Thats the next thing I'm doing, Ima put stainless works long tube headers on my truck

 

Not to jack your thread MCH but I was thinking of putting highflier and longtube headers on my self, do u guys know if logtube headers fit in place of stock manifolds without any mods under the hood?

 

They will, however they are a royal pain to install. Right up there with the 5.4L spark plug change out except nothing "should" break in a header install. There is a PDF install guide from Dynatech over-viewing the install.

 

I'm just glad i have all the resources to do headers when i get them lol. I lately have been throwing a P0430 on certain tunes when mashing on the gas to pass with my high flows but i have no issue with them rattling around and breaking up like my stocks gave me!