i just got my longtubes and damn do they look good, i'll try to post some pics tomorrow,my questions are where to place the cats, i am going to use the 3inch y pipe and does magnaflow make hi flow cats that are 3in/3out? any help would be great

 

Sounds like a plan. Great call on the 3" Y. Yes Magnaflow offers 3" cats that will operate for these trucks, part #s 94009, #94109, and #94315. These are all 3" versions of the standard 2.5" cats that work on these trucks.

 

darren thanks for the reply, which cat of those would be the loudest? i'll have another question for you once i post the pics, o2 sensor related

 

If I'm not mistaken the OBX long tubes uses a 2.5" Y pipe not a 3".

 

94109 would be since the 94100 series cats are 9"s long ( the shortest body out of those listed ) The rear O2s get mounted after the hi-flow cats to keep the CEL out.

 

good to know now the headers have 2 bungs per side before the cats any idea what these would be for as i only have one o2 per side right now mounted in the middle of the cat?

 

https://www.f150online.com/forums/me...fx4-screw.html

 

Those bungs in the LTs are for the front O2 sensors which measure air & fuel ratio. Your going to need extensions for those which I would imagine are included in the LTs. Your front O2s are way up near the manifolds, built into the downpipes.

 

i don't have any extensions and last time i looked it looked like there was only the 2 o2's built into the cats but i'll look again, i got the headers and y pipe shipped for 300 was an open box but it all l ooks good, any idea where to get extensions

 

 

Try RPMOutlet.com they should have the extensions for your truck.

 

Good looking LTs.