I have a 2006 Ford F-150 5.4 v8 and I want to get an exhaust for it and I want it to be loud, anyone know of a good exhaust

 

How loud you want it? Do the free exhaust, sawzall off the muffler, through the pipe just after the y comes together. That's what I did. Saved hundreds and get compliments all the time on the pure sound of the 5.4.

 

Okay so I have done that before and it sounded amazing I was just wondering if there was a way to replicate it and still be able to pass emission test

 

It's a common misconception people have. Mufflers do nothing for emissions. That's what catalytic converters are for. Mufflers simply muffle the noise. Not sure in your state if they demand a muffler, but in two states I've lived in I've been through many emissions tests with three different vehicles without mufflers and passed every time.

 

So I already have a high flow cat installed so I don't know if I could past emissions with just that. That's why I was wanting a exhaust but if can past it with just that then that would be great

 

Like i said, mufflers muffle noise, they don't do anything for emissions. If you don't pass with the high flow cat, you won't pass by adding a muffler.

I'm running high flow cats as well, no CEL, no problems ever passing emissions. Truck has been tested in two different states. Both of my cars had the same setup, never a problem passing emissions.

 

Like nddragon stated .. they are not measuring for noise.. just emission gases

 

In the People's Republic of Kalifornia, a muffler is part of the visual inspection since a muffler is part of the original equipment package. Its part of the emissions "system" even though it does nothing. A lot of people get away with it, but you CAN get failed without a muffler here.

 

Oh okay so then what about horsepower does it lose some and since there not much back pressure how does that affect the performance if I don't use an exhaust

 

I just installed flowmaster super 44s duals. They have a deep sound but not a very loud sound. After 2k rpm the sound does not get louder. If you are thinking flowmasters get the original 40s.