I was recently looking at some headers for my 92 f250 4x4 auto, 351w and I came across a lot of stuff dealing with emissions. I was thinking of getting some hedman headers and noticed they have a few different kinds for the 351. They have some that look like full length headers with a 3" collector part #89270 that says it includes emissions parts but no A.I.R. or smog stuff. Then there is part #89421 that looks like more of a shorty header with a stock collector and an A.I.R. fitting. I looked at my truck today and on the passenger side there is a fitting on the front that leads to a tube that goes to a piece with part number A34 and E8TE-9F483-B2A that looks like some kind of regulator or valve or something that is bolted to the intake manifold and has an electrical connector coming off of it. Is this part of the AIR system? What does the AIR system do? If I get the headers with no fitting for it will the truck still pass emissions? or even run? The next part of my question deals with the cat. I have 1 huge cat on my truck with the 2 exhust pipes from each manifold going in and 2 hoses connected on top. Why are there hoses on the top? if I were to get a high flow cat or a pair of high flow cats (one for each side) would I have to get ones that had a connection for the hoses on them? Would it pass emissions with regular high flow cats? What are the 2 hoses connected to and can I remove them? Thanks for any help anyone can give me.

 

I'm not too keen on the parts or the lines, I myself have a pair of hooker shorties that are off of a 89' GT so my thoughts are that they will be legal (seeing as I don't have emissions where I live.....yet).

When I did my 93' to a point of your plans, the only tube I had was the air tube, nothing else. I did have the same converter though; two pipes into one outlet over the c-member, I chopped it all off and when it came time for the new pipes not one shop would do the work, so in turn I took the time to cut and weld and cut(it became a vicious cycle) but got it to somewhat of a nice system, cheaper but took me about a month to complete with my schedule.

Basicly with the federal emissions you'll end up doing all the work unless you have people that do this type of work.

 

The hoses on the top of the cat is for the A.I.R injection tubes. The AIR pump forces air into the cat through those hoses to help the exhaust burn a little bit more.
A high flow catalytic converter will give you a bit more power and burn the exhaust better than a stock one. I had an 83 F-150 and I had the entire exhaust system replaced because the stock cat blew all of it's beads into the muffler and ruined it. I had a high flow cat put in, and it really helped the truck pass the sniffer and it ran better than the day I got it.
If I were you, I would go to a dual exhaust, but I would stick to one cat and get a cat-back system. It's a lot cheaper than 2 catalytic converters.
As for the headers, if you get non-emmisions parts, it will fail smog, fail the visual test and cause your ECM to go haywire because you have to have fitting to put O2 sensors and AIR injection tubes and if you don't, the computer will make the truck run rich.....very rich.

 

The O2 sensor on the truck is farther down the pipe after the manifold ends but before the cat, it has a little pipe welded between the 2 and the sensor is attached to that little pipe. So the O2 sensor would stay on the system regardles off the headers. The only thing attached is that tube right off hte front of the passeneger manifold, nothing on the drivers side. Cant wait to get the system ripped out and throw in some new pipes, cat, and dual 45 degree behind the rear wheels. So I should probably get the headers with the attachment for that AIR fitting right? or is that fitting not that important/can be removed?

 

sorry to steal a thread but, w/my O2 sensor it's as BC478 decribed fitted between the two pipes, when I did the exhaust it developed a crack around the little pipe, would this cause a problem??

 

351w have a egr valve that what your looking at it's part of emission system
some header come with those openings and some don't
there have been 4 style 351w's engines and a 351m

 

so essentially I cant take the EGR system off becuase hte truck will fail visual inspection and maybe emissions and the ecm would go nuts and throw out error codes. The problem is that I dont think hedman sells any of their long tube headers with the attachment for the EGR, they only sell almost exacly stock headers except for the fact that they are tubular with teh fitting. I wanted go with long tubes cuz they are better for performance and sound. How much of a difference is there between long tube and shorty performance? does anyone know of a company that sells long tubes with the EGR fitting on them? or could I make a fitting and weld it to the headers? Thanks for all the help everyone.

 

make a fitting youself