Headers or Stock Manifolds?

Hey all. I'm thinking about trying to save the few flailing brain cells I've got left by pushing the noxious exhaust gases as far back into the slipstream as possible. In pursuit of a custom bent dual exhaust, should I go to some decent headers or just stick w/the factory manifolds? Optimum performance is not the ultimate priority. A leak free solid exhaust system that won't gas me out is what I'm after. Regards, -K-

PS - Oh yea,...this is for my '78 CJ-7 w/the 304.

 

Leak free? Stock manifolds

 

:iagree: :iagree:

I ran headers on my truck for the better part of a decade, and wish I'd just kept the old log manifolds. Unless you safety wire the bolts, they'll always back out...then the gaskets burn, then you have leaks. You get used to tightening them. You also get used to replacing the gaskets when you're too lazy to tighten them . The collectors generally stay put, but it's another place to get a leak that manifolds don't have. They're louder than stock manifolds too. If you want every ounce of performance, go for it. With a stock or mildly build motor, I wouldn't bother.

 

There always seem to be a debate on headers vs manifold. When I picked up my jeep I noticed the headers it had on were rusted out(literally). I replaced them with another set of headers over a year ago and haven't had to tighten them since(with the original bolts). I very was surprised when I checked them a few weeks ago and they were still just as tight as before.

I've seen a lot of trouble with headers coming loose though. My cousin had to tighten the headers on his 350 weekly, until he bought split lock header bolts.

Since performance is not your ultimate goal with the engine then I'd just stick with stock manifolds and save the head ache most seem to experience.

 

I run headers on both jeeps. Stock manifolds would be quieter, less hassel and leak free. I don't mind the extra work of the headers. I like the sound they give the jeep. I run inside the frame headers on green jeep with dual exhaust out the rear. It is actually pretty quiet. Black Jeep has fenderwell outlet headers, now that one is a tad loud. I think it is kind of cool to open the hood and have headers in there too. Maybe one day I will grow up, doubt it...

Whenever I install new header gaskets I put them on, run the car/truck, then with the headers still hot tighten the bolts again. The heat seems to soften the gaskets. I use Mr. Gasket header gaskets. When I put them in like that they usually (not always) stay tight. Safety wired header bolts would look pretty trick....

 

How 'bout all the modern headers that all the magazines brag about these days, with their "ultra thick" flanges, special locking bolts, etc. etc. Examples would be the Edelbrock shorty's, or the Thorley headers. Are all the "improvements" they claim just marketing, or has header technology improved over the years? Headers used to be dirt cheap, and now they are very expensive, even without ceramic coating.

I ask because I am in the same situation trying to decide which way to go.

 

Having a 64 CJ you are probably used to tinkering with your Jeep. If you go with the headers you can add another item to your list of things that needs to be tinkered with on a semi regular basis. To get a low maintenance set of headers you will spend big money. If you buy good ones and have them ceramic coated they will last for years. If you buy cheap ones you will watch the black spray paint burn off the first time you fire it up. I bought a set of fender well jobs for my V6. After watching other guys off roading with steam constantly rolling out of their fender wells I decided not to use mine. Every mud hole or puddle you drive through the front tires throw all that crap on your headers. I noticed you mentioned fume/leak free driving? Go with the stock manifolds. Just my opinion. I have ran both but would not go back to headers. Need a set for a Dauntless?

 

The AMC V8 exhaust manifolds are pretty good as cast iron manifolds go. The cast iron manifolds are quieter, put less heat into the engine compartment (less radiative surface), leak less, are sturdier, and much less expensive than headers. Headers are strictly race-car tech IMO.

You might want headers if you ran an engine with really dreadful iron manifolds, like most FE Fords. For them the choice is between the nearly unobtainable Hi-Po iron manifolds, the common and very restrictive iron log, or aftermarket headers.

 

Here's a question. Some AMC V8 engines have the dog leg style exhaust ports. Are the exhaust manifold or headers interchangable between all AMC V8 engines? Or, if you have dog leg style ports, then do you need to also have dog leg style exhaust?

 

I think, yes, you need to match the manifold to the port style, but I'm not sure. I don't think the port style is relevant to Jeeps, except for maybe the 1971 FSJs which got the 360 first. I think that all or almost all of the 304-360-401 engines got the dogleg port heads, and the 290-343-390 may be different.

 

Thanks for all the great information, and I've gotta say "thanks" to all for not serving it up with a bunch of attitude. You guys may know that I screw around with old air-cooled VW's too, and I know a fair bit about 'em too but the community around the hobby seems to have gone kind of cranky and elitist lately. Sure makes me want to hang around here a lot more often. Regards, -K-

 

Does anyone know a source to buy replacement stock manifolds or have a good source for a used set?

 

On headers you get what you pay for. I have a set of jet coated jba ramhorn on my dodge truck for over 10 years no leaks no loose bolts, I have a set on my jeep (came with them on) I had one loose bolt in 3 years. That was after I put on my Clifford intake. That could have been my fault. With the temp extremes of headers you need THICK flanges.

 

Some manifolds are available new - search the net.

Are you missing manifolds? Old manifolds can be surfaced if they leak.

Try the classifieds here, or one of the Wagoneer forums like www.ifsja.org Sometimes you can find stuff locally and cheaply through your local 4x4 and Jeep forum. Also maybe Pirate - those guys are always throwing away stock parts http://www.pirate4x4.com/forum/

Last resort would be one of the big Jeep wreckers like J&W or Scottys (there are one or two in AZ and CO too IIRC) or there's a very dated list of all-AMC wrecking yards.

No need to resort to that though - they're common.

 

I have headers on my 79 CJ. I've only put 400 or so miles on it since purchase and have checked the bolts after every fill-up. Mine are staying pretty tite. The jeep came with a Cat-converter and headers and is about as quiet at idle as my z71. I'm thinking the cat has to go.

 

Something to watch for when searching for the cast manifolds is the drivers side. Make sure they're for a CJ because I "believe" they were a different style on some of the FSJ's. Maybe someone could confirm this?

 

Drivers side should be a center outlet. The rear outlet man. exits right over the clutch linkage pivot.
Thanks for bringing this up. I was on the fence over headers on my 360. Now I'm sticking with the manifolds.