1. 4 or 6 cyl ?
2. what do you plan to do with your jeep?
3. how much $$$ do you want to spend?

-all of those companies make a good product that is legal in the socialist republic of Kalifornia. Clifford also makes one if you have the six (dunno if they make one for the 4).
-more flow on the backside of the engine will not do much for you without increasing the flow into the other side of the engine.
-it will raise your power band to a higher rpm (lose a bit of low end torque, or rather moves it)
-if you have a six it will make it sound a little louder (alos depends on what you put behind it (you are going to have to screw around with the rest of the exhaust if you switch to a header.
-if you get a stainless of HPC coated header then they should last a very good long time

-thats about all i can think of right now as my house is getting ready to float away

-web

 

I look at it this way..... Headers will add some HP IF and only IF the engine is suffering from an exhaust restriction, and that hardly ever occurs under 5000 RPM.

The stock exhaust manifold for the 4.0 has pretty good, header-like flow already. Headers CAN be trouble long term with leakage and so forth.

 

good headers with good flow mufflers might get ya 10-20 horses on a v-8 go figure??

 

In reply to:

I look at it this way..... Headers will add some HP IF and only IF the engine is suffering from an exhaust restriction, and that hardly ever occurs under 5000 RPM.

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And the other side of that coin is .... Headers will cost some HP at lower RPMs. Exhaust systems have a scavenge effect where the exhaust from one cylinder helps pull the exhaust from the next cylinder similar to a siphon.

Yep, headers might get ya 10-20 horses on a v-8 but that's at one and only one given RPM value. It starts dropping off either side of that.

For the past 30 years, automotive engineers have been trying to squeeze every fractional horsepower available from the smaller engines. If headers worked, they would have used them and in some cased have used short versions. But, if your driving style is totally different than what the engineers expected by only making 1/4 mile trips and accelerating from a standing stop to 200+ MPH, the headers are for you.

 

i have the same problem. what i have found is you can buy an aftermarket header cheaper than a mopar replacement manifold. just replaceing the manifold with a header will basically be an unoticable power difference. now the truth is these cheaper headers are just that cheaper. i have seen some custom manifolds on ebay with expansion joint on the front and rear exhaust ports. they are also cheaper than mopar replacements and seem to be as good. Has anyone used one of these?

 

I've never liked headers on a street driven vehicle, not even my fast street cars! The HPC coatings have brought them a long way in the way of lifespan, but they just don't last long term. They end up leaking and cracking (the problem you are fixing) and rusting. They just aren't worth the hassle.
On a 10 second drag car that you are revving to peak RPM in all gears... YES, but in a Jeep that sees most of it's work load in the 1500 to 2500 RPM range, just not worth the hassles. Get a new manifold is my opinion.
If you do get a header, get it HPC or Jet Hot coated (ceramic) and get one with the thickest mounting flanges and tube thickness you can find, it will last the longest.

 

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=33632&item=2433170610
heres what i was talking about.

 

When I rebuild my CJ7 completely, I did a header. I didn't like it because:

- lots of extra heat under the hood and near the brake lines
- Far less clearance - I had problems near the auto tranny and proportioning valve.
- Did not add any performance until above 4000rpm, where I will never run my Jeep at
- Caused the engine to run lean with too little backpressure, it was impossible to tune

I switched to a factory exhaust manifold. It runs much better, cooler, and I have many less routing problems.

I would suggest you find a good used factory manifold, and use it. Just make sure it is flat first ($20 to get it surfaced). Headers are just not worth the hassle (my opinion).

 

its all about air flow, from the top of the intake to the combusion chamber ,threw the head or heads to the entire exhaust system with least amount of restriction as possible,port and polish all the runners and match all the tubes so that all air , intake and exhaust flows freely,and to have no turbulance to cause more back pressure and weeken the flow and power.
my 97 mustang has factory headers, wonder why?? to increase HP on V6 3.8 ..i bet ,, not for looks.
DEX
my 2 cents.
98 more and i'd have a dollar. LOL LOL

 

I'd say no to the header. You wont gain much, if anything from a header on a stock TJ. So theres really no benefit. Also you'll most likely have problems sealing it. They always seem to leak after a few months. And worst of all...the amount of heat they add to the engine compartment just doesnt outweigh the small, if any benefit they provide. Personally, I'd put a new manifold on...stock style.

remy

 

end of question and answers? we all have our own appion and not all agree to all, thats why this is America, freedom of speech.

 

why always comments? all we need is help and let the rest go if ya dont understand post ???

 

FWIW here's my take:

My jeep came to me ('75 CJ-5 304 V8) with fenderwell headers and cherry bombs (glass packs). My plan is to make it a daily driver so the glass packs are just too much noise, the fumes exit right under the seats, and they were rusty and leaky.

My first thought was to go back to stock configuration. After pricing manifolds and parts and seeing that the "Y" tube to join the 2 sides together was hard to find, I decided to go with hedman in-frame headers and dynomax super turbo mufflers (2). The system was about 300 bones from engine to tailpipe with about 2 weeks of part time work. It still has a nice rumble, but it doesn't rattle windows. Here is a thread about it with some pictures from the headers back: header pics I am pleased with the result.

I don't expect this to be a forever solution, I just hope it keeps me on the road a couple years while I collect the parts to do it right. I have already gotten a set of used manifolds.

The headers do put out a fair amount of heat, but it has not caused any problems in the engine compartment. That may be due to the fact that there were already headers in there before. The PO told me that he had to put in copper plug wires because the standard (carbon?) ones would break down and cause missing. You are also on your own (or at the mercy of a muffler shop) for the rest of the system after the headers.

Good luck with your deliberations

 

Distraktion was looking for opinions, advice and reasons and I think we have all given fair assesments for all. In a single statement, "Headers make more horsepower". On the surface this is true. They make more 'Peak' power, just as adding high flow intake system, big tube exhaust, flowmaster muffler, ported and polished intake/exhaust ports and combustion chambers and bigger valves do. But, big power numbers on the peak or top end of the RPM scale don't do you any good in a Jeep that does it's crawling in the 1500 rpm range or on the road in the 2500-3000 RPM range. These "High air flow mods" actualy hurt performance and efficiency in these areas by reducing torque in the bottom end of the RPM scale. Would I do these mods to my Road Runner? Of course, every single one of them, they make sense for the RPM that the vehicle works in.

Opinions are freely asked and given, just because someone doesn't agree with you, doesen't mean they or you are wrong. We have just come to different conclusions through research...which is fine. God Bless our Freedom.

 

In reply to:

Will they make my Jeep more fun?

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Yes, I think they will do this more than they will improve performance.
You are mostly paying for the noise that they make, which is cool with me!
They sound really good on an AMC V-8 w/ glasspacks.