Hi-
I'm new to the forum and had a couple of questions to ask you guys. I have a 98 expedition and have a crack in one of the exhaust manifolds, now bc i live in northern ny and bc ford used steel bolts in an aluminum head this job could be a nightmare. But anyways... does anyone have any recommendations for headers to replace the stock manifolds, Also I live in NY as previously stated where they just changed inspections on 96 and newer vehicles to a computer and emissions test and want to make sure i can still pass with headers, would also like a set that is hassle free and will bolt rite on, I would appreciate any advice

Thanks in advance
Justin

 

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I can't comment on the headers b/c I've never used any. Others may have a different opinion, but unless you're planning on doing other modifications the slight power increase from them (which you probably won't feel anyway) may not be worth the hassle of replacing / retrofitting to aftermarket. I would just buy a used factory manifold from a junkyard and only replace the broken one.

You'll likely find the header studs aren't too bad to get out. I had a problem with 2 of my studs on the passenger side of my Y2K Xpe 5.4L breaking off, which caused a exhaust header leak and the rest of the exhaust system rattle too. I did this repair last year and despite the header being very rusty, the studs all came out either by hand or with vice grips. Good Luck & Welcome to the FTE Forum!

 

I would definately go for the aftermarket headers. You factory exhaust manifold is very restrictive and headers are probably the best performance upgrade out there for the money. You can find them at: www.summitracing.com.

As far as emissions, most if not all of the aftermarket headers are emissions legal and should be a direct fit. Your ecu will recognize the increased flow and slightly leaner condition and make corrections to re-trim the fuel and ignition maps. You can speed this up by pulling the battery cable for a few minutes and forcing the ecu to re-learn the parameters quicker.

I have had headers on most vehicles I have owned and the increases are always noticable. I am putting them on my Expedition soon as I finish tuning my turbo charged Acura Integra.

 

I really doubt headers on a SUV will be as noticeable as an Integra, but that's just my guess. Factory "headers" aren't as restrictive as they used to be because they're fluid tested during the engineering process, unlike the old days where they just made them to fit.

Also consider the argument that less exhaust back pressure reduces torque. One of the nice things about the 5.4L is the low end torque it puts out for a small engine. Its the feel that impresses your friends when you floor it and put them back in their seats. Reducing exhaust back pressure usually reduces low end torque.

Longtube headers are a different story, but bolt on factory replacements suck in my opinion. They are usually not made as well as factory and just invite those hillbilly sounding exhaust leaks from gaskets blowing out. I had them on my '93 Mustang GT and the speed shop owner said it would really be noticeable. BS!!!! that was a waste of $125 and a day busting knuckles under the hood and under the car. You'll also need to upgrade the rest of the exhaust, muffler, cats etc. to take full advantage of the headers.

Do a search on the forum here and the F-150 section. I'm sure there are posts about bolt on headers with people who've tried them commenting.

 

I really doubt headers on a SUV will be as noticeable as an Integra, but that's just my opinion. Factory "headers" aren't as restrictive as they used to be because they're fluid tested during the engineering process, unlike the old days where they just made them to fit.

Also consider the argument that less exhaust back pressure reduces torque. One of the nice things about the 5.4L is the low end torque it puts out for a smaller engine. Torque is the feel that impresses your friends when you floor it and it puts them back in their seats. Reducing exhaust back pressure usually reduces low end torque.

Longtube headers are a different story, but bolt on factory replacements suck in my opinion. I had them on my '93 Mustang GT and the speed shop owner said it would really be noticeable. BS!!!! That was a waste of $125 and a day busting knuckles under the hood and under the car. You'll also need to upgrade the rest of the exhaust, muffler, cats etc. to take full advantage of the headers.

 

thanks for the advice guys. I thik i'll hold off on the headers and maybe do a cat-back system in the near future

 

I personally did Gibson stainless headers with a Gibson cat back and it made a tremendous improvement in sound and acceleration. A few things I ran into when replacing the headers..... a couple of the studs were broke, but were easily removed, the oil dipstick has to come out (this I ended up having to replace), and EGR tube and adapter, also it's easier to get the headers in if you unbolt the motor mounts and jack the engine up a couple if inches. Took about 3 hours to complete using air tools. In my opinion it was worth it and I don't have any regrets about doing it. Hope this helps.