Comments: First header went on well and had good power, but a leak started about 6 months later. Turned out to be a cracked weld. A stainless header with Ceramic is now in at no cost.
Their purrrty. Click on any of my posts to access the pictures available online.
Cons
Overkill for a DD
Recommended
yes
Comments: The Doug Thorley headers for the 4.0L have excellent construction and are ceramic coated. Easy to install and hook up. Any performance to be gained would require additional components installed on both the front and back end of the intake conducive to increased and less restrictive air flow.
Ceramic coated, very durable, great sound/performance
Cons
Pricey
Recommended
yes
Comments: Great replacement for the crappy factory manifold which is known to crack. Purchased and installed a Doug Thorley ceramic coated header about 8 years ago, still looks new. No rust on this thing at all and have run it through numerous trails. Repainted when engine was rebuilt. Also gives the 4.0L great sound and noticeable performance.
+Torque seems the same as before (with other mods), but there's a large difference above 3200 RPMs; pulls hard to 5000 (4.0L)
Cons
-Cost
-Install is a giant pain
Recommended
yes
Comments: Installed a Thorley HDX-635 this past weekend with a Magnaflow 50899 front catalytic converter y-pipe and Flowmaster universal rear cat. It's attached to a MBRP XP Series T-409 cat-back exhaust, a 63mm throttle body and an AEM cold air intake. (Jeep is 6-spd with 33s & 3.73s)
The intake, throttle body and cat-back exhaust were already on my LJ.
The headers and y-pipe rock!!! They're expensive and a pain to install, but I would do it over and over again. The Jeep MOVES now. Can't wait to try it on the trail, but it's a stop light dragster now! The headers also sound great; there's a throatey warble that wasn't there before.
Definitely worth the price if you're into power from a 4.0L!!!
:drool:
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