GM Gen. III & IV Small Block V8 Engine Mounts


XJ Cherokee & MJ Comanche Jeeps

Building the perfect GM LS Vortec Gen III+ engine mount for the unibody XJ & MJ Jeeps was an engineering feat. After several relentless renditions, installations and tweaks, these mounts are as close to perfect as we know how to make them.

Jeep XJ MJ Engine Mounts for Chevy V8

Kit MMXJ3, engine mounts, GM Gen III engines into XJ Cherokees & MJ Comanches

Kit contents:

  • Frame bracket weldments
  • Engine plates
  • Isolators, upper and lower
  • Fastening hardware
  • Instructions

Ease of Installation

These mounts are bolt-in style and detailed instructions (see the PDF link below) will guide to an ideal installation. We do recommend a weld be placed on these mounts on the top lip (and sides too if you would like) for the best strength achievable.


The Novak mounts feature thick 3/16” laser cut and CNC bent steel construction. The formed frame brackets hug the Jeep unibody frame, creating a plate steel overlay that will add rigidity to this most important part of the Jeep frame. Generous welds, smart geometry and multiple attachment points will attest to their strength.

Vibration Isolation

Each mount kit comes with our high-grade urethane isolators that are specified for that ideal balance of isolation and firmness with the power of modern engines. Substantial 5/8” through bolts capture the assembly. Replacement bushing sets are available below should replacement ever be needed.


Geometry of the mounts is compact to provide clearance for all stock components including the steering shaft with its pillow block and the recommended exhaust headers below.

Engine Mount Finish

your engine mounts arrive in a black zinc, rust resistant finish but may also be painted to suit your installation.

Applications & Compatibility

Compatible Jeeps

These mounts fit all 1984-2001 XJ Cherokee, XJ Wagoneer & MJ Comanche platform Jeeps.

XJ Jeep with LS Style Engine

Compatible Engines

These mounts will fit the GM Gen III & IV LS/Vortec V8 engines. *Note, that stock truck style intakes and accessory brackets will not clear the hood on these applications.Vortec engines will require Corvette style intakes and accessories for hood clearance, power steering gear clearance, cooling fan clearance, and best overall layout for an XJ / MJ. However, we do recommend the truck style oil pans. Please read the installation links below for more information.

Gen V engine mounts are also available. Contact us for these.

Customer Dean N. and his LS style install

Customer Dean N. and his late 1990's XJ with LS Engine

Related Products

Headers for Jeep Swap Engines
Engine Mount Bushings, spares
Radiator for GM Chevy engines in XJ Jeeps
Pilot bushings for Jeeps

Installation Requirements

Unbolting and removal of the factory frame mounts for factory engines is required. Steering remains as per factory. A lift kit and bump stops may be required to correct for sagging factory springs and clearance requirements for your GM oil pan. This and many other important details are covered in our provided instructions.


These mounts are a purely bolt-in design. Once the old mounts are removed and the engine bay is cleared and prepped, the #MMXJ3 mounts can be installed rapidly. All fastening hardware is provided. The installer will need to have a 7/16-14 tap to thread a blank body insert.

Read Novak's detailed and most recently updated Cherokee and Comanche Gen III & IV conversion instruction package as provided with our engine mounts.


XJ Jeep Frame Overhead

Also See

Image Gallery

2-Door XJ with LS Engine

Installer C. Lambski and his 2-door XJ

LS engine in Cherokee with Holley Terminator

4Lo's Rich Klein and his XJ with LS engine, topped with a Holley Terminator intake and control system

LS powertrain and Cherokee Jeep

The Lambski Cherokee with LS powertrain in the foreground

LS Cherokee Alternator

A Corvette style alternator and power steering arrangement in the Nesbitt Cherokee

LS Cherokee passenger engine compartment

Battery, hose, AC and cooling system in the Klein XJ