if im not mistaken the 04-05's have 4 cats and 06-08's have 2 cats and i was wondering if i could swap my exhaust for an 06-08 with 2 cats from where it bolts on to the manifolds to the mid pipe. i have a flowmaster 10 si/do and it's not nearly as loud as an 06 with 2 cats and the same setup.

 

dont feel bad that mines louder lol

 

im so jealous lol i want that sound, i think it'd be easier to swap a stock exhaust from a junkyard than hi flow cats

 

prolly would...is there any o2 sensors on your back cats?

 

yep, 4 O2 sensors but if i swapped and ran codes i could erase it

 

hmmmm...what if u got those o2 delete things?

 

the 02 spacers? does yours have 2 or 4

 

2....jus unbolt it all and leave them hangin under your truck and run open manifolds...theres no way thatd be bad for it lol

 

i mean if i wanted to i could unbolt the exhaust and weld in two hi flows myself or just gut the rears but still

 

going from 4 to 2 cats will not throw a code...

 

even with 4 sensors?

 

yep, all 97+ f150's have 4 sensors

 

figured since mines 06 i only have 2 cats so id only have 2 sensors...i may have 4 sensors but ive never noticed?

 

yes, you have 4, 1 before each cat, and 1 after each cat

first one reads the a/f the second one is for emissions, that is why the rear 2 cats (which are mounted after the second o2 can be removed, there is no sensor after them to see if they are there or not

 

but do the 06+ only have 2 cats?