Swapping a HEMI engine into a Jeep Wrangler is a popular modification among off-road enthusiasts. To ensure a successful and seamless installation, it is crucial to choose the right install kits and mounting brackets. This article will explore the best options available, ensuring your HEMI swap is as smooth as possible.

Understanding the HEMI Swap

The HEMI engine is known for its power and performance, making it an excellent choice for a Wrangler upgrade. However, the swap process requires careful planning and the right components. Here are some key considerations:

  • Compatibility with existing components
  • Engine mounts and transmission options
  • Electrical and cooling system modifications

Before diving into specific kits, it pays to understand the common HEMI variants used in swaps: the 5.7-liter (345 cid), 6.1-liter (370 cid), and 6.4-liter (392 cid). The 5.7 is the most accessible and fits with minimal firewall or frame modification. The 6.4 offers more power but requires careful attention to headers clearance, oil pan selection, and transmission adapter matching. For JK and JL Wranglers, the 6.4 HEMI from the SRT8 or Dodge Challenger is a popular donor, while TJ and LJ owners often prefer the 5.7 for its balance of power and bolt-in simplicity.

Top Install Kits for Wrangler HEMI Swaps

When selecting an install kit, look for options that provide all necessary components for the swap. Here are some of the best install kits available:

RIPP Superchargers HEMI Swap Kit

RIPP Superchargers offers a comprehensive kit that includes engine mounts, transmission adapters, and all necessary hardware. Designed primarily for JK Wranglers, this kit supports both 5.7 and 6.4 HEMI engines. The mounts are CNC-billet aluminum and CNC-machined from 6061-T6 alloy for strength and consistent fitment. The transmission adapter allows the use of factory 42RLE or NAG1 automatic transmissions, or you can order with an adapter for the NV3550 manual. The kit also includes a high-pressure fuel pump conversion bracket and instructions for wiring integration. RIPP's kit is often praised for its robust drivetrain alignment and clear documentation. Visit RIPP Superchargers for current pricing.

Novak Conversions HEMI Conversion Kit

Novak Conversions has built a reputation for quality HEMI swap parts, particularly for TJ and LJ Wranglers. Their complete conversion kit includes engine positioning brackets, transmission adapter plates, a custom wiring harness for the 5.7 or 6.4 HEMI, and a pre-calibrated engine control module (PCM). Novak uses a patent-pending mounting system that moves the engine rearward for improved weight distribution and clearance for front axles and suspension components. The kit also includes a re-routed power steering pressure line and pre-formed heater hoses. Novak’s wiring harness is designed to be plug-and-play with most Wrangler chassis wiring, reducing the complexity of the electrical portion of the swap. Learn more at Novak Conversions.

GenRight Off Road JEEP HEMI Swap Kit

GenRight Off Road specializes in heavy-duty off-road parts, and their HEMI swap kit reflects that focus. It includes heavy-duty engine mounts, transmission crossmember brackets, and high-strength steel skid plates. The mounts are designed to fit both JK and JL Wranglers with 5.7 and 6.4 HEMI engines. GenRight's kit includes motor mount isolators that are much thicker than factory parts, minimizing engine movement during hard wheeling. They also offer optional transmission adapters for both automatic (8HP70, NAG1) and manual (NSG370, AX15) gearboxes. Many builders appreciate that GenRight's brackets are sold separately for those who already have some swap components, allowing modular purchases. Browse GenRight HEMI swap parts.

Shaffers Off Road HEMI Swap Kit

For those working with earlier TJ Wranglers, Shaffers Off Road produces a dedicated HEMI swap kit that uses factory-style isolation mounts and includes an adapter for the Dana 44 front axle to clear the 5.7 HEMI oil pan. Their kit features a one-piece steel engine bracket that bolts to the factory frame mount locations without requiring welding or frame slotting. The transmission adapter accommodates both AX15 and NV3550 manual transmissions. Shaffers also supplies a pre-terminated engine harness with a modified PCM calibration specific to the Wrangler VIN, making registration easier in emissions-inspected states. See Shaffers Off Road swap packages.

Essential Mounting Brackets

Mounting brackets are critical for securely positioning the HEMI engine in the Wrangler. Even with a full kit, quality brackets make the difference between a reliable daily driver and a project that constantly requires adjustment.

Rugged Ridge HEMI Engine Mounts

Rugged Ridge offers a set of engineered engine mounts for Wrangler HEMI swaps, available in both standard and heavy-duty configurations. The mounts are constructed from heavy-gauge steel and use rubber isolators to reduce vibration. They are designed to fit JK models (2007-2018) and require no frame modification. The isolators are replaceable, allowing you to swap in firmer polyurethane inserts if desired. These mounts are frequently used in conjunction with Rugged Ridge’s transmission crossmember and engine skid plate to create a complete driveline package.

Energy Suspension Polyurethane Engine Mounts

Energy Suspension produces polyurethane engine mounts specifically for HEMI swap applications. Polyurethane offers superior durability and vibration dampening compared to rubber, especially important for off-road use where engine torque and shock loads are higher. The mounts are direct replacements for the factory-style rubber mounts but with a stiffer formulation that resists sagging and tearing. Energy Suspension mounts also include stainless steel sleeves and grease fittings for longevity. Many builders choose these when using a non-isolated motor plate system to minimize engine movement inside the chassis.

JKS Manufacturing HEMI Mounting Brackets

JKS Manufacturing is known for their strength and reliability. Their HEMI mounting brackets are laser-cut from ¼-inch steel and powder-coated for corrosion resistance. The design allows the engine to sit as low as possible in the chassis, improving center of gravity and hood clearance. JKS brackets include provisions for both the driver and passenger side, with slotted holes for adjusting fore-aft position even after the engine is installed. They also offer an integrated sway bar mount relocation kit for JK models when using longer arms upstream. JKS brackets are sold as a pair and work with most aftermarket rubber or polyurethane isolators.

Additional Components to Consider

Beyond the kits and brackets, several other components are necessary for a successful HEMI swap. Overlooking any of them can lead to delays or performance issues.

Transmission Adapters

Transmission adapters bridge the flywheel/flexplate pattern of the HEMI engine to your transmission’s bellhousing. Common options include:

  • Advanced Adapters Atlas Transfer Case – Allows use of the factory NV241 or NP231 transfer case with an LS-style bolt pattern adapter.
  • Mopar HEMI to 42RLE Adapter – OEM parts direct from Mopar for 2007-2011 JK automatic Wranglers.
  • Quick Time Bellhousing Adapters – For manual transmissions, these provide SFI-approved protection and allow use of standard clutch kits.

Wiring Harnesses and PCM Tuning

Swapping a HEMI into a Wrangler requires adapting the engine’s control system to the chassis. Hotwire Auto and PSI Conversion offer stand-alone wiring harnesses that integrate with the Wrangler’s power distribution and instrument cluster. These harnesses typically include a harness-in-a-box that connects to the factory OBD2 port for diagnostics. PCM tuning is equally critical: Flying Dutchman 4x4 provides custom calibrations for emissions compatibility and performance. Without proper tuning, the HEMI may run lean, set fault codes, or fail to start.

Cooling System Upgrades

The HEMI’s increased heat output demands a larger radiator, dual electric fans, and possibly a high-flow thermostat. Many swap kits include an aluminum radiator core with increased capacity. Be sure to upgrade the coolant recovery tank and use a 180-degree or 160-degree thermostat to keep engine temperatures in check during low-speed off-road crawling. For JK Wranglers, the Mishimoto HEMI swap radiator is a popular choice, offering a direct-fit design with a lifetime warranty.

Fuel System Upgrades

Most HEMI engines require a returnless high-pressure fuel system operating at 58 psi (400 kPa). This means upgrading the in-tank pump and fuel lines. A dedicated HEMI swap fuel pump module from AEV or Bryson Fuel Systems can replace the factory pump assembly. If your Wrangler originally ran a return-style system, you’ll need to convert to a returnless setup or use a regulator designed for dead-head applications. Stainless steel fuel lines (AN-6 or AN-8) are recommended for durability and easy routing.

Exhaust Manifolds and Headers

Factory HEMI exhaust manifolds often interfere with Wrangler steering shafts or floor pans. Shorty headers from Borla or Flash Fab provide better clearance and flow. For TJ swaps, headers that tuck close to the block are essential to avoid the front differential. Ceramic coating helps reduce underhood temperatures. Consider a dual exhaust system with a transverse muffler to save space.

Installation Tips for a Seamless HEMI Swap

Even with the best parts, installation mistakes can derail a project. Follow these guidelines to keep everything smooth:

  • Test-fit the engine and transmission together before final welding or painting. Check clearance to the firewall, steering shaft, and front differential. Use modeling clay on tight spots to confirm clearance.
  • Torque all drivetrain bolts to factory specs – engine mount bolts (e.g., 46 ft-lbs for JK frame mounts), transmission adapter bolts, bellhousing bolts, and crossmember bolts. Overtightening can crack castings; under-tightening causes vibration and failure.
  • Invest in a quality wire harness – avoid splicing into the base HEMI harness unless you have deep experience. A pre-made harness saves weeks of troubleshooting.
  • Use a transmission jack adapter to support the transmission while aligning the engine. A single misalignment can ruin a pilot bearing.
  • Pressure test the cooling system after routing hoses and before final fill. Air pockets in the HEMI water jacket can cause hot spots.
  • Break in the engine properly – after starting, vary engine RPM between 1500-3000 for 20 minutes without idling, following the camshaft manufacturer’s break-in procedures. Use a high-zinc break-in oil for flat tappet cams or specific guidelines for roller cams.
  • Check all wiring connections with a multimeter before connecting the battery. A single incorrect pin-out can fry the PCM.

Common mistakes include forgetting to install the pilot bearing in manual transmission swaps, using incorrect flywheel bolts (the HEMI uses a metric thread specific to Mopar), and failing to support the weight of the transmission during installation, which can crack the adapter plate.

Conclusion

A HEMI swap can significantly enhance the performance of your Jeep Wrangler. By selecting the right install kits and mounting brackets, you can achieve a seamless installation. Always remember to plan ahead and consult with experts to ensure the best results. Whether you choose a kit from RIPP, Novak, GenRight, or Shaffers, pair it with robust brackets from Rugged Ridge, Energy Suspension, or JKS. Incorporate proper transmission adapters, wiring, cooling, and fuel system upgrades. With careful preparation and attention to detail, your Wrangler will deliver HEMI power reliably on and off the trail.