First of all, I'm rockin the 2005 f150 fx4 5.4 with the flowmaster super 44..

So i read a million threads on here about which cat to get, and it looks like everyone was going with the 94106 and just mounting the o2 sensor behind it... welll.... all the muffler shops i went in to said they could not do the install since the o2 bungs are in the middle, so the o2 sensor won't reach to behind the cat. also said the cat is not round (to fit in its place by the heat shield)

I contacted the seller on ebay whom i purchased from and he said

"The ones you will need is Magnaflow 99356hm. Round cat that is 49 state legal with o2 bung in the middle. 2.5" inlet and outlet."

"Huh, that's weird. According to Magnaflow the 5.4 4wd doesn't have the o2 sensor in the middle. The 4.6 heritage edition shows the o2 sensor in the middle.. it's a round style cat with o2 bung in the middle. The 94106 cat wouldn't have worked for you anyways for a 2005 vehicle. It would have set off a check engine light. If you read the description I specify this cat is only recommended for vehicles 2003 and older. Let me know what you would like to do and I will set it up."

so what would you guys recommend me do?

 

The exhaust shop could make them work if they take the time to do it right. Dropping the downpipes, cutting at the bend, using mandrel 2.5" 45'd bends, installing cats, then the O2s would go in their same general location. The #94106 cats are shorter than OEM cats and will work fine as long as your 2005 is not running rich.

 

what bulbs are you running in your fogs Darren ??

 

I have the 94106's on my '07 5.4 currently...had the O2 sensors mounted a little ways behind them.
It took awhile but did eventually start throwing codes....you can either drill out some sparkplug, non-foulers which is the cheaper route, or buy 2 heat sink, bung extenders.
I went with the non-foulers and haven't gotten another code.

 

Oh yeah, one more thing....the motorcraft O2 sensors are a lil longer on the 04-08s making the non-fouler mod a lil trickier. I found the "standard motor products" O2 sensors to fit a lot easier...part number SG459.

 

This^^^

I'm running the 94106 with no issues for about 4000 miles now. We had to bend new flanges and I also welded in 5 new bungs, 1 for a wideband 02 18" away from cylinder number 8 (drivers side). No extensions on the 02's were needed and I also made some non fouler's fit in the rear 02's for good measure.

The 94106 is in fact a OBD 1 cat, so it technically should throw a catalyst inefficiency code due to the lack of precious metal content they contain. OBD 2 cats contain more precious metals to clean more effectively, but they are double the price. This is why some guys need to run spark plug non fouler's in the rear 02's.

I've got pics, but the forum app is acting screwy.. Prob need to delete and reinstall the app.. (I noticed a lot of people having issues and double posts)

 

well since none of my muffler shops want to mess with it obviously.. what do y'all recommend me do?

 

What king of muffler shops are in your area?? Mine installed my two cats, relocated the downstream O2 and installed the new upstreams i bought for $130, didnt think twice. Its not like your asking them to break the law...

If nothing else can you return your cat and get the one with the bung in it?

 

What 02 sensors did you use?

 

For the non fouler mod:
You just need to make a hole in the heat shield to allow the 02 sensor top to protrude through it.. The heat shield is aluminum so a drill bit to route it out is all you need..

Just make sure you knock down any sharp edges in the shield that could cut the wire.

The factory rears hardly ever fail. If they are bad then go to rock auto and pick up the motorcraft part.. They are cheap and plug right up..