1)1987-06 General Engine Conversion Information


Engine conversions for off-road vehicles are popular with both old & new models. We have been involved with engine and transmission conversions for more than 30 years and are not surprised when we see a new vehicle with less than 10,000 miles having an engine swapped. Since you are venturing out beyond the boundary of the corner gas station and local repair shop, you should be aware that off-road driving is quite different than street driving. Once you pull onto a dirt road, your vehicle must be capable of returning you and your passengers back to civilization. The best, single reason for an off-road 4WD engine conversion is reliability. If your 4WD cannot deliver this, then you're in serious trouble. Make sure that when making a change on your off-road vehicle it is done with the best equipment and design available. Don't short change your conversion for components that will give you less reliability.

There will always be situations where more power would be nice such as when towing a trailer, turning those big new tires, or falling short from the top of a hill. A common mistake of many off-road drivers is overpowering the existing drivetrain. If additional power is required and the stock transmission specifications and rear axle torque rating have been exceeded, then you might be required to use a stronger substitute. Jeeps have been equipped with several types and sizes of engines. In order to assist you, we have listed the various stock engines that were used throughout these years.

150 CID 4 Cylinder Engine TBI (1987-02)

148 CID 4 Cylinder Engine (2.4) (2003-05)

258/4.2L CID Straight 6 Cylinder (1972-90)

4.0L Straight 6 Cylinder (1991-05)

2.8L V6 Engine (Cherokees) (1984-86) GM

2.5L V6 Engine 151 CID (XJ) (1984-00) GM

4.0L Engine (XJ) (1987-01)

2.4L & 3.7L Engine (KJ) (2002-05)


Select a motor which best fits the use of your vehicle. We manufacture motor mounts, bellhousing adapters, headers, and transfer case adapters for Chevy, Chevy Gen III V8's, Ford, Dodge & Dodge Hemi, Buick V6 & some AMC motors. Within these range of motors, every practical need can be met.


Many people become overly concerned about moving the transmission, resulting in driveshaft modifications. The value of a good engine location requiring driveshaft modifications will far exceed the expenses of an installation requiring special cooling due to poor engine location.

We design most transfer case adapters to eliminate driveshaft modifications (whenever possible). This normally pertains to the newer type Jeeps with the longer wheel base. In order to position your new engine, it is usually mandatory that the original engine mounts be removed from the chassis. When placing the new motor into the chassis, several factors determine the best possible location.

A. Firewall Clearance: Allow adequate clearance between the distributor & firewall. Be sure that the distributor can be removed easily. Make sure the engine can be worked on without having to remove it from the vehicle.

B. Front Axle Clearance: Check the oil pan and harmonic balancer for axle housing clearance. Double check the suspension clearance if bottoming out. Location of the motor mounts will require some vehicles to relocate their front axle snubber.

C. Hood Clearance: When the air cleaner is in position, will the hood still close? On certain applications, special low profile air cleaners or a 1” body lift may be required .

D. Driveshaft Clearance & Angularity: The front driveshaft should have sufficient clearance to pass the bellhousing and starter. On vehicles 1987 & newer, the drivetrain may have to be offset towards the passenger side or centered in the frame rails. Make sure that the driveshaft's do not bottom out when the suspension is collapsed. The angle of the rear driveshaft is very critical, and compensation can be made by either axle shims or lowering the transfer case.

E. Radiator Clearances: Proper spacing and centering of the fan with the radiator is necessary for optimum cooling. If you are having a problem in this area, an alternative is an electric cooling fan. These fans are popular for engine conversions, since they can be mounted on the front or backside of the radiator and don't require engine placement considerations when using an engine-driven fan.

F. Exhaust Manifold/Header Clearance: If headers are planned for the vehicle, it is best to purchase them before the installation of the engine. Although we make headers for several different applications, a perfect fit can never be guaranteed. When locating the engine, have the headers or stock manifolds in place and check the following for clearances: firewall, brake & clutch pedals through travel, steering box or linkage, body & frame, heater/defroster, and battery. When placing the engine into position, be sure and have your engine exhaust system mounted on the engine. This ensures all proper clearances are maintained.

I. Oil Filters: Oil filters can be a real problem especially on Ford conversions. The filter on Ford engines is locate up front on the driver's side, and this can interfere with the stock steering or suspension components. If additional clearance is needed, we suggest a remote oil filter. We offer remote oil filter kits for most engines.

J. Motor Mount Installation: The motor mounts we manufacture are designed for specific applications, along with some universal applications. Some are a bolt-in style, while others require welding. The universal mounts are designed to fit a variety of frame widths. The channels that extend to the block are slotted, allowing a choice of engine placement.

“L” brackets on weld-in mounts should be welded entirely around the perimeter. All welding should be done by a certified welder. When using a double donut design mount, make sure that the donuts properly index to the “L” bracket and the bolts are properly tightened. Mount bolts should be checked periodically.

Once the engine has been selected, you will now need engine mounts. We offer several combinations that will fit Ford, Chevy, Dodge, and Buick blocks. On most Ford and Chevy applications, we standardize our mounts by using a special dual rubber donut, locked together with special hardened bolts. This combination offers a positive means of securing the engine for the most severe off-road conditions.

Most of our mounts are universal and can be adjusted to accommodate the best possible engine location, while others are very specific and offer no alternate for changes. Our universal Chevy and Ford side mounts are the most popular style for Jeep engine conversions. The mounts are furnished so that they can be either welded or bolted into position, and are fully adjustable so that the engine can be offset.

The universal mounts are now available in two styles; one for the Jeep universals, and one for the wider framed vehicles that will fit up to 30.500" frames. We also offer a saddle-type mount for Chevy engine conversions that works well for vehicles with frames from 25" to 30". In the Buick V6 category, we also offer a universal Buick V6 engine mount that utilizes our double donut design and is fully adjustable, similar to the Chevy and Ford engine mounts.

In conjunction with all engine mounts, you will need to use a rear cross member mount. This is usually the same mount with a new location adjusted to the new engine position. Two mounting points are all that is ever required with most installations. This will allow for plenty of engine flexibility and will eliminate transmission and engine vibrations.

We have been doing engine conversions for over 40 years . We've learned the hard way to count only on top-quality & proven design installations. Our mounts are secured with a 5/8” diameter bolt between the engine brace and frame bracket. No rubber vulcanization failure will let you down. To assure that you have the premier engine mounts that we offer, make sure our name is on the box. Do not accept look-a-like takeoffs. We are the “4-Wheel Drive Experts” and have the quality to prove it. 4.3 INTO YJ 5 SPEED

K. YJ Steering Shaft and Mounting upgrades: The stock steering shaft normally does not present any clearance issues with new engines. We have found that as these Jeep get older, the stock steering shaft does develop end play. We now carry heavy duty replacement steering shafts for Jeep YJ's. Jeep's original steering shaft assembly was not designed for the added stress of body lifts and oversize tires. We carry the Bergeson's replacement assemblies which have a telescoping shaft with two precision needle bearing u-joints. The steering assembly is easy to install with common hand tools. Once installed, you will experience much tighter and more responsive steering.


Steer your Jeep YJ easy without interference. This new mounting plate moves the YJ steering box 1” forward, increasing the clearance between the tie rod and drag link. This provides more clearance making it less likely to have steering bind. This mounting plate is made with 1/2” steel for strength and reliability. P/N 716855

Universal Motor Mounts Jeep YJs: The universal mounts we manufacture are a high quality mounting system. The “L” brackets in these kits are made out of 3/8” material and designed to handle any style of driving. These universal mounts allow for lateral and vertical placement in the frame rail to maximize you drivetrain fit. The installation of these mounts will require the removal of you stock engine mounts.

Chevy V6 & V8:

P/N 713001-S - 1987-1996 Jeep YJ Chevy V8 motor mounts

P/N 713005 - 1987-1996 Jeep YJ Chevy V8 LT1 motor mounts

P/N 713088 - 1987-1996 Jeep YJ Chevy V8 Gen III & LS1 motor mounts

Ford V8:

P/N 713006 - 1987-1996 Jeep YJ Ford small block V8 motor mounts

Buick V6:

P/N 713011 - 1987-1996 Jeep YJ Buick V6 motor mounts

Dodge V8 & Hemi:

P/N 713095 - 1987-1996 Jeep YJ Dodge V8 (318/360) motor mounts

P/N 713097 - 1987-1996 Jeep YJ Dodge Hemi motor mounts

1987 to 1996 Jeep YJs: We offer a bolt-in saddle motor mount for the Chevy engines. This mount is designed to replace both the stock 4 & 6 cylinder Jeep engines, and is designed around a stock oil pan. If you are using an aftermarket oil pan, the maximum depth in the front is 3-5/8". This motor mount will not work with LT1 or 383 Stroker motors.

We have designed this mount to position your new engine in the best location possible. Driveshaft modifications may be necessary depending on your application. This mount will allow 1-1/4" of overall adjustment from front to rear. The stock Jeep motor mounts need to be completely removed from the frame before installing the new saddle mount. An electric fuel pump is required for ALL applications.

Chevy V8:

P/N 713087 - Chevy V8 to Jeep YJ (bolt in mount)

1997 to 2005 Jeep TJs: We now offer motor mounts for Chevy and Mopar engines. The mounts are designed to replace both the stock 4 & 6 cylinder Jeep engines and also work on both stock and lifted TJs; however, a 1” body lift is recommended on most applications and required on Gen. III engine installation.

Chevy V8:

P/N 713090 - Chevy V8 to Jeep TJ 4 cyl. replacement (bolt in mount)

P/N 713091 - Chevy V8 to Jeep TJ 6 cyl. replacement (welding is required)

P/N 713092 - Gen. III V8 to Jeep TJ 4 cyl. & 6 cyl. replacement (welding is required) JEEP TJ 5.3 GEN 3

P/N 713093 - Gen. III V8 to Jeep TJ 4 cyl. & 6 cyl. with AC replacement (welding and frame mods. required)

Dodge V8 & Hemi:

P/N 713094 - Dodge 318 to Jeep TJ 4 cyl. & 6 cyl. repl. (welding is required)

P/N 713098 - Dodge Hemi to Jeep TJ 4 cyl. & 6 cyl. repl. (welding is required)

Chevy V6:

P/N 713096 - 4.3 V6 to Jeep TJ 4 cyl. & 6 cyl. replacement (welding is required)

Advance Adapters “Off Road” Mounts: We carry an “Off Road” series motor mounts for the hard core 4-wheel enthusiast. These mounts are a weld-in design that use a horizontal neoprene isolator. These mounts are designed to handle the abuse of the roughest type of trail

P/N 713206 - Jeep YJ & TJ Stock Rubber Mount Replacement

Jeep Cherokee XJ Mounts: We manufacture motor mounts for installing a Chevy V6 or V8. Our mounts require the original motor mounts to be removed from the frame rails. The engine mounts will set the Chevy engines at a height that will provide minimum hood clearance. Engines equipped with throttle body fuel injection, will need to modify the air cleaner.

A suspension lift is mandatory in order to have the proper suspension clearance. Failure to use a suspension lift will not provide the proper engine clearance which will cause both engine and suspension damage. The engine mounts are designed for a direct bolt in conversion. The stabilizer assembly on the driver's side will need to be reinstalled to the new engine mounts.

P/N 713109 - Jeep Cherokee to Chevy V8 mounts

P/N 713117 - Jeep Cherokee to Chevy V6 mounts