Ive got a 99 f150 5.4 with two flowmaster mufflers not sure whichones they were there when I bought the truck I recently cut the pipes off and dumpped the mufflers downward for some reason it got quieter so im going to have the pipes put back on hopefully upgrade them to a 3" instead of a 2.5" will that make it louder? But I also want high flow cats which ones are good for good price also will i pass inspection with high flow cats and does it mess with my sensors? Thanks guys

 

So do you have duels then?

 

Yes I have duals

 

True duals ?

 

First of all, cut the mufflers off.

 

Honestly I dont know how to tell if they are true duals

 

will i still pass inspection with no mufflers? and I want it loud but to still sound nice wont having no muffler sound kinda bad?

 

Dont change to a larger size, only run 3" if its a single intermediate pipe system.

If theres dual intermediate pipes, and two mufflers.

 

Yes I have duals then ill take a picture

 

well here is some pics also how would i know if i already have high flow cats? i really apreciate the help

 

You for sure have stock cats. Replace those 4 stockers with two Magnaflow 94106 cars and you should be happy. There was a recent thread by Joshchester, he recently added in hi-flows to his SI/DO 40. Check it out.

 

High flow cats will definitely get you the sound you're looking for. Those 4 stock cats are killing your sound. I didn't realize how bad it was till I did high flows on my truck, and the difference is amazing.

 

Thanks i will do that wheres the best place to get them any suggestions? I saw some new ones on ebay for 70 each with shipping

 

hey what about the sensors and inspection everything will be good there? i live in texas i dont know if that makes a difference

 

Another vote for High Flows. Really opens it up. Yours will sound similar to mine.