Jeep JK V8 swap: why a Hemi is better than an LS engine

Which is better: Chevy or Mopar? That long-lived debate is hard to settle unless you’re talking about Jeep engine swaps – then the answer is undoubtedly Mopar. While LS engines are great, there’s no substitute for a powerful Hemi engine in a Chrysler Corporation product, like the Jeep Wrangler JK.

Don’t get us wrong; we love LS engines. In fact, we produced a Chevy conversion for many years. But there’s one major problem with the Wrangler LS swap: it isn’t smog legal. At least not in California and other states with similar emissions laws. Plus, getting a Chevy V8 to work in a Chrysler product is troublesome, to say the least.

Our Hemi kit, on the other hand, is California Air Resource Board (CARB) approved. Also, installation is straightforward in the 2007-2011 Wrangler JK. And that’s why the team at Jeep Speed Shop has stopped performing LS swaps to focus solely on Mopar conversions.

The whole story…

Here at Jeep Speed Shop, we have a motto: ‘if we can’t do it right, then we won’t do it at all’. For years, we fought to make a CARB legal LS kit. Unfortunately, the state fought back by issuing stricter emissions requirements every year.

Then, in 2016, California ramped up its restrictions on engine conversions, making a legal LS JK swap nearly impossible. Although the decision was difficult, that’s when Jeep Speed Shop decided to stop doing Chevy conversions.

We now devote all of our effort towards Hemi-powered Wranglers – and we haven’t looked back. LS swaps breed problems that make the conversion a losing cause.

Wrangler JK LS swap problems

At Jeep Speed Shop, we understand the allure of stuffing a Camaro or Silverado engine into a JK. That’s why for years, our team attempted to make a smog-legal conversion. In the end, though, we found the swap just isn’t worth it for the following reasons:

    • Not smog legal: As was mentioned earlier, the most significant deterrent is that LS JK swaps aren’t California smog legal – and they probably never will be. All Chevy-powered Jeeps must have a special adapter box and tuning, making the conversion impossible to get past the CARB.
    • Repair confusion: Diagnostic and repair difficulty skyrockets when you blend a Chevy with a Mopar. In many instances, customers who perform the LS JK swap themselves can’t tell if they have a Chevy issue or a Jeep issue when problems arise.
    • Mixed brands: California is much more lenient towards same-brand swaps, so we were able to get the Hemi conversion approved, but not the LS kit. Trying to legalize the Chevy swap got too complicated; CARB required the donor truck VINs be from California emissions vehicles, so we could not use new engines.


  • More problems: Before, Jeep Speed Shop would do any generation LS conversion pulled from any GM vehicle – car, truck, whatever. That led to all kinds of fitment problems and mechanical issues. Each conversion was a test of our patience, as well as the patience of our customers.


Basically, shoehorning a Chevy engine into a Jeep is like trying to stuff a square peg into a round hole. Although it’s possible, you need a Sawzall, torch and a lot of dedication to make it happen. Keeping everything Mopar is a much better option.

Wrangler JK Hemi swap solutions

Although the LS swap didn’t work out – at least not in California – there’s a better JK V8 conversion: the 5.7L Hemi. By going 100% Mopar, the team at Jeep Speed shop has made life easier, both for ourselves and our customers. These are some of the perks of putting our Hemi kit in your JK:

  • CARB smog legal: Our Hemi conversion kit is 50-state smog legal for 2007-2011 Wrangler JKs. That means you can take your ride to a standard emissions station, just like any other vehicle. No referee needed!
  • Easier conversion: Swapping a Mopar engine into a Mopar vehicle makes for a straightforward conversion. Chrysler tends to use similar parts and installation methods in all its products.
  • Fewer problems: The engine and the vehicle work well together because they’re both Mopar products. In fact, the Hemi fits perfectly in the JK; it’s as if Chrysler intended to make a V8 Jeep from the beginning.
  • C’mon – it’s a Hemi! Sure, LS engines are great, but nothing beats a Hemi. The 5.7L that comes in our complete kit (there’s also a DIY package where you supply the engine) is rated at of 390 hp and 407 lb.-ft. Also, it features variable valve timing (VVT) and a multiple displacement system (MDS) for maximum efficiency.  

We can testify firsthand that the Hemi swap is much easier – and better – than the LS conversion. Jeep Speed Shop owns a 2008 JK with an LS and a 2011 Jeep JK with a Hemi. While the Chevy swap left us wanting to pull our hair out (it needed a lot of tuning and transmission work), the Mopar was comparatively simple.

Are you ready for raw, unadulterated Hemi power?

The Hemi conversion is by far the best V8 swap for the Wrangler JK. When you’re ready to scrap that stock V6 and get eight-cylinder power, visit Jeep Speed shop. Our complete Hemi kit (with engine and transmission) includes:

  • 100% new 5.7L Hemi crate engine (390 hp, 407 lb.-ft.)
  • 100% new  545RFE automatic transmission
  • Brand new alternator, AC compressor, power steering pump and belt
  • New cooling system components including a fresh radiator
  • Specially-tuned PCM complete with wiring harness

We also offer a DIY kit where you supply the engine. Highlights include:

  • Easy installation with step-by-step instructions
  • All necessary hardware included  
  • Specially-tuned PCM complete with wiring harness
  • New radiator

Best of all, the conversion is CARB-certified and 50-state emissions legal! Take your Jeep to the trail on the weekend and legally drive it to work on Monday. An LS conversion will be out of the question, once you’ve experienced our flawless, easy-to-own, Hemi swap. Call / text  us now at (707) 338-3154 or complete our Contact Us form and we’ll get right back to you.  If you are in the area, stop by today to begin the transformation of your Wrangler JK!