Stock Dorman vs. Which Header ??

[ChiefRocka]

Hey Guys ...

Just gathering some info on replacement exhaust manifolds.

The aftermarket ranges from 150 to over 500 for headers.

I can get a Dorman stock replacement for cheap.

Cheap Stainless headers can be brittle, and crack as well.

When I first acquired my Jeep, I removed the manifold, and welded up all the cracks. In fact, I also added some triangle braces in between tubes to help strengthen the manifold.

It has held up well, but other cracks have come back.

So it is time !!

I would prefer a 'header', but the Dorman with bellows seems a good choice too ?

Anyone care to chime in on what they/friends have used ??

Thanks !

:keegirl:

[4.3LXJ]

The word header is kind of misleading with the 4.0. It actually has a shorty header, not the cast iron type. And no one makes a long header for it. So you are stuck with that design. And you are right the six tube design does crack. Not sure about the bellows, but I seems a good idea to prevent cracks

[ChiefRocka]

The aftermarket is more of a tri design.

If I had more time, I would just jig up my stock one, cut off the tubes and make my own using stock flanges.

Stock replacement is where im leaning

[ches30]

I have a new dorman in the box need to install.


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[grainofsalt]

Just thinking here, But have you checked your motor mounts? If they are shot the flexing of the motor will crack any header.

Just my .02!

[s1xty7]

I have come up with my game plan for attacking this problem. I have a 1998 with a stock intake manifold too so I don't have to worry about any sort of clearance issue just yet. Anyway, the cracks seem to stem from additional leverage on the exhaust manifold/header. I had a flex pipe installed in the middle of my down pipe, ordered a new Anchor transmission mount from RockAuto.com, and have a new set of Brown Dog motor mounts on the way with their ultra-flex rubber. Once those are in, I'll install my new APN header and hopefully everything will be squared away.

One thing to note about my flex pipe install. It appears that the new flex section being welded in has caused an odd resonance at about 1800 RPM. It almost sounds like a power steering pump working (in fact I replaced my power steering pump because of it). I'm hoping that once everything else is put together the resonance will go away otherwise I will be revisiting that part of it.

Good luck as this seems to be a long term issue for a lot of people. My Jeep is my DD and I plan on keeping it so I don't mind sinking a few $$ into it to hopefully solve the problem once and for all.