2007 Jeep Wrangler JK Build-Up 2007 Jeep Wrangler goes from Mild to Wild


Coated Headers Ready to Ship

Check out our new headers. They are Jet-Hot coated, designed for either 5.7L or 6.1L Hemis. These are the best headers for this swap by far!


2008 JK with 5.7L Hemi

We just finished this 2008 JK. It now runs a 5.7L Hemi, 5 speed auto transmission, Superlift 4" kit with Bilsteins, 20" XD Spy wheels, and 35x14.50x20 Pit Bull Growler tires.

Also, this is the very first Jeep to have our Jet Hot coated production headers!

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Hemi Conversion Parts For Sale

We have started listing Hemi conversion parts for sale on our site. These pieces are either hard to find, or made by us specifically for this conversion.

We are also starting to do turn-key installs. Turn-key vehicles can be as simple as just a Hemi swap or as much as finding a vehicle and setting it up with lift, tires, wheels, seats, Hemi, etc. to your specs. Please call us at 800-954-0065 for information on turn-key set-ups


Teardown Video

While we are waiting on the Jeep to get back from the exhaust shop it has given us some time to update the web site. Here is a video of the initial teardown:

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First Start Video

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Hemi Install Finished!

We finally finished the install this week.  There are a few small things to polish, but it is ready to run. We are loading the Jeep on the trailer today so we can take it to the dealership tomorrow to have the VIN and PIN updated in the new computer so it will start.  Then it is off to get the exhaust fabbed.

We plan on putting up video and more pictures after those steps are finished (and it is a little warmer outside).  Feel free to ask questions about the conversion.

F.Y.I.  Our 4WS headers for Hemi conversions in the JK should be available in 6-8 weeks!  Here are the highlights of our header design:

  • Install with engine already in place
  • All tubes are near equal length
  • Jet-Hot coated to reduce under-hood temperatures
  • 3" collectors with O2 bungs
  • Works with large 5.7 starter (no need to mini starter)
  • Longer tubes than OEM to give more low end power
  • Works with 5.7L EGR port or 6.1 without EGR port
  • D-shaped ports in manifold to match 6.1, but will still allow free flowing exhaust on 5.7
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Hemi Headers (Jeep JK)

I have spent a lot of time researching headers for this swap. I have seen what other companies have used and I have talked to experts in the header/exhaust industry about this issue. The goal of this article is to explain the problems with all headers available for Hemis as they relate to the 07-08 Jeep Wranglers.

OEM 6.1 Header/Manifolds are a big step up in design and performance compared to a log style manifold that you would find on most vehicles. These headers wouldn't be too bad for this conversion. What you will find is that the car version of the headers sticks out too far and will not fit between the frame, so those are out. The other option are the Grand Cherokee headers. Not only will the Grand Cherokee headers cost about a grand, but they won't work wit the stock short arm set up. They should work with most long arm kits (like the Rubicon Express kit). If you are running short arms the passenger's side collector will be right in your upper control arm mount. I have seen where other people have cut, sectioned and moved the mount. Personally, I don't like moving and reusing the stock suspensions mounts because they are heavily engineered and modifying them could jeopardize the structural integrity. Finally, with any of these headers, they are relatively short tubed and do not have equal length tubes for all ports. The result is a high rpm power band and decreased performance.

5.7L shorty headers will work, but there are some problems. The passengers side collector is real close to the frame making the exhaust "interesting". Also, the ports on a 5.7 and 6.1 are VERY different. See the picture to the side with the 6.1 exhaust gasket on a 5.7 header. That is a huge reduction in flow. Also, the shorty headers will move the power band even higher in the rpm range because of the tube lengths. Finally, the tubes are nowhere near equal lengths for each port, reducing performance.

Our decision was to custom make some templates for the longest tube headers possible in this application with as close to equal length tubes as possible. We will be producing and selling these headers just for the 5.7 and 6.1 Hemi JK conversions. Our headers will be designed to work with short arm suspensions as well as most long arm kits. Best of all, our headers will be the same price or less expensive than most of the alternatives.


Hemi Mounted, Nearly Finished

Sorry about the delay between updates.  The engine is mounted with the tranny and t-case bolted in as well.  We have fabbed some mounts for the Hemi, and will be coming out with a nice production mount that will be available for sale soon.  The clearance is tight, we are hugging the steering shaft pretty tight, about 1/2"-3/4" from the hood and will have to trim the battery tray to get it back in.  The transmission we used requires a different mount for the transmission and t-case shifters.  We also had to fab a plate for the new transmission mount.   We were able to use a lot of stock hoses and lines.  Right now we are working on getting some custom transmission cooler lines produced, a new fuel line, new A/C lines, and some radiator hoses.

The biggest delay from today to finish is going to be the headers.  I am going to write another entry later today about the headers, because it is a big issue with this conversion.

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Ready to Install

We have the engine mated to the transmission. The wiring harness made by Suier, Inc came in (along with a new computer). The harness fit perfect. The only thing to watch out for is that on the 07 and newer Hemi's the crank positions sensor plug is smaller than what is on the harness. If you order a new sensor off an older Hemi (like 04), it will bolt right in place and has the right plug. I talked with Squier about this and they are already working on making another harness with the new style plug. To route the harness, you will need to remote the intake manifold, no big deal.

So...today we pulled the Jeep in the shop. So far we have removed the grille, radiator, condenser, O2 sensors, air box, drive shafts, and a bunch of bolts, hoses and other small parts. No surprises yet (other than how rusted the exhaust bolts are after so little time). We will post some pictures and VIDEO of the teardown, then a lot more pictures of the install.

We will be keeping close track of what parts are needed for this swap, and what parts will swap over from the 3.8 to the 6.1. Check back often for information on what you need for the swap and what to watch out for along the way.

P.S. We will be installing Superior Chromoly axles soon and put up info on that as well.

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The Engine is Here

We just received the engine last week. So far we have the engine, transmission, engine accessories and starter. The main thing we had to change was the flywheel. The stock flywheel on the crate 6.1 was a different pattern than the one for the 545RFE that we have. Our transmission is a used 5-45RFE out of a 2004 Ram 1500 4wd. We ordered a new flywheel for the 5.7L, which mated to the 6.1L just fine. The part number for the flywheel (flexplate) was 4736604AA, it has four holes for the torque converter at 3, 6, 9 and 12 o'clock positions.

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