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The Jeep Utility Wagon

Jeeps in this category are easy to convert to GM V6 & V8 power. These will always have a T90 three-speed transmission. There were also some optional T98 four-speeds in the 1955-1964 models.

We get inquiries about putting straight 6's in these vehicles, but usually advise strongly against it due to the very poor fit caused by the short distance between the firewall and the front cross member.

A small block Chevy V6 (esp. 4.3 FI) and V8 will give respectable performance and better mileage than any straight-six and either are far easier to install than the straight-six.

Transmissions
The stock Jeep T90 three-speed is a decent transmission, and many choose to retain it while converting. If choosing this route, consider a good rebuild with quality components to prepare it for a stronger engine. They are easily and affordably adaptable to Chevy & Buick power.

Utility Jeeps with 6-226 (or 1962-64 with 6-230 OHC) engines have the proper input gear in the T90 transmission and our kits for these vehicles take this into account. Utility Jeeps that had the 4 cyl. or 6's, other than 6226 or 6-230, will have a 15/16" diameter short input gear and will have to have the "conversion" input gear installed in the T90. These transmissions use the same kits as the 4 cyl. CJ5.

The Novak #C1 and #C3, T90 to GM bellhousing adapter we manufacture is used in conjunction with a sealed front transmission bearing retainer. The bellhousing, flywheel, clutch, clutch release arm, and clutch release bearing are GM style parts. It should be noted that the Jeep V6 and Buick V6 clutch, pressure plate, release bearing, and release arm are interchangeable with these same parts from a Chevy V8. On CJ Jeeps, the use of the Jeep V6 release arm (Novak #RAV6) will simplify connecting the clutch linkage, although any Chevy arm will work if shortened to where it ends up about 5-3/4" from the pivot ball seal to the point where the linkage attaches. The earlier model Chevy cast iron bellhousing is stronger than the 1962 and newer aluminum housing but either one will work for conversion purposes.

For conversions where the installer is looking for a lower-geared and stronger transmission. Follow the hyperlinks for further informative details. We feel the best options are:

If installing a manual transmission, you should definitely read our Guide to Clutches, Linkages & Bellhousings.

When retaining the T90, you can leave your transmission and transfer case in the same position, whereas, the aforementioned conversion transmissions all require relocation of the transfer case and subsequent changing of the length of the driveshafts.

Transfer Case
The Dana Spicer Model 18, as found in these Jeeps is an excellent transfer case. It has all the strength required for even the strongest V8's. Its compact size, excellent servicability and offset design allow for great conversions and more adept four-wheeling. As for the T90, you may wish to inspect and possibly rebuild your Model 18 with quality components.

Engine Mounts
Removal of the stock frame brackets is required to make way for the new engine. We recommend our #MMX mounts. They make for a clean, strong installation, and their versatile adjustability makes them ideal for a variety of conversion options. They are typically welded on to the Jeep frame for the best results.

Engine Placement
Front to rear location is determined by firewall clearance on these short engine compartment Jeeps.

Engine mounting height is critical on these Jeeps as the front axle assembly is further back in relation to the engine compartment than on CJs. If the engine is mounted too low in front, starter to front drive shaft clearance will be insufficient. Additional front mounting height can be obtained by denting the firewall in at the area of the right cylinder head and distributor. The pre-1975 distributors are conventional point type, interchangeable with, and smaller in diameter than the 1975 and new electronic units. Early Utility models may require slight modification of the firewall for distributor clearance. Late 1950s and newer usually do not. Use of a point type distributor will allow about 1-1/2" higher front engine mounting position if you are using a 1975 or newer engine.

The Utility series has a 27-1/2" wide frame.

Vertical location is important for proper front drive shaft to starter clearance. Avoid the common error of mounting the engine too low in front. Keep in mind that the suspension height will change when the weight of the engine is placed on the frame. What appears to be sufficient engine to front differential and front drive shaft to starter clearance with the engine hanging on the hoist could be insufficient when engine weight is placed on the frame. Also, the engine should be mounted about three to five degrees high in front, as measured by the carburetor plate of the intake manifold (see photo at left).



These Jeeps actually have the original engine mounted offset towards the drivers side. The original engine/transmission assembly is offset 1-1/4" towards the driver on these Jeeps. The transmission and transfer case assembly does not have to be moved over or forward when installing a V8 with the T90.

With the engine attached to the rear mount via the transmission, and side to side location established at the front, the engine support arm bolt hole location can be determined. Do this by clamping the frame bracket in place and marking or center punching the support arm through the hole in the frame bracket. Drill the support arms with a 7/16” or 15/32” drill and assemble the special urethane isolator parts and bolts, as per the following diagram.

The frame brackets can be ”C” clamped to the frame (below) and the weight of the engine can be put on the suspension for a vertical height check. If correct, the frame brackets can then be welded to the frame. It is a good idea to pre-heat the frame brackets and frame rails with a torch before applying the final weld. It is not advisable to attempt to bolt the frame brackets to the Jeep frame unless spacers are welded between the frame sides to prevent the frame sides from being pulled together by the bolts. Installing spacers is more involved than welding the frame brackets to the frame.

Final Assembly
At final assembly of the mounts, do not over-tighten the bolts that go through the urethane insulator cushions. Note that we have provided a step in the isolators to lock them onto the new frame brackets. When properly tightened, the mounts will provide a very secure fit. The bolts should be tightened enough to keep the engine from moving but no so tight as to squash the urethane cushions. Over-tightening will cause excessive engine-to-frame vibration as well as early failure of the cushions. After the first nut has been properly tightened, put the second nut on and tighten it as a jam nut against the first, using two wrenches.

You may wish to follow up with a sandblasting or wire brushing of the frame and mounts, followed by a good priming and paint.

Exhaust
A tight fitting, block hugging style manifold or header is recommended for clearance of steering components. Fenderwell exit headers are a solution, but sometimes a sloppy one - not to mention the vortex of exhaust fumes that they often cause to swirl into the Jeep. It is best to run the exhaust through a Y-Pipe and run it out the back of the Jeep along the inner side of the driver's side frame rail. Leave clearance for brake and electrical lines.

Cooling
A radiator will fit between the conversion engine and the front cross member. Refer to our cooling article. The stock Jeep radiator, if in good condition, should cool a V6. See our extensive write-up on cooling for some good guidelines.

Fitment
The following crossmember work pertains only to V8 and is not required for V6 installations. (The shorter V6 will clear the crossmember and can be cooled with the stock Jeep radiator if it is in good condition.) A new front crossmember for the V8 should be located in line with the front of the grille. It is best made from 1-1/2" x 3" rectangular steel tubing of 3/16" wall thickness, or from 3" channel iron. It should fit back into the "C" section of the Jeep frame. For a stronger installation, "box" the frame horns with 10 or 11 gage steel in front and behind the new crossmember. If stock Jeep steering is being retained, then the bellcrank bracket must be remounted on the new crossmember. The drag link and tie rods will have to be lengthened to accommodate the new location of the bellcrank. A better solution to the steering problem on any V8 swap is to convert to Chevy Saginaw steering. The steering shaft can be run under the new crossmember.

Regarding steering conversions — a steering conversion should only be done by someone who is knowledgeable about the procedures involved and has the correct parts, tools, and has the ability to weld properly.

The battery will have to be moved from its stock location. If a small 12 volt battery is used, it can be relocated on the firewall. A battery holder from a 1972 or newer CJ Jeep can be used for this purpose.

Fantastic for making your own clutch, throttle and even transfer case shifter linkages, these bearing ends, combined with threaded rod, make outstanding linkages.

Clutch Linkage
Clutch linkage on Jeeps with 6 cyl. engines was totally different than those with four-cylinder engines. Different procedures are used for linkage with the Chevy V8 swap. Because all current Chevy arms are too long, one will have to be modified for use with the six-cylinder version of the Utility linkage. This arm should be 6" long from the pivot point to where the linkage pull rod attaches. If the original threaded adjuster block is used on the upper arm of the crosstube, a new pull rod can be made up with clevis and rod end bearing. Alternately, an eye and pin could be used at the release arm end of the pullrod, if you don't want to bother with the rod end method just described.

The four-cylinder clutch linkage is modified by welding an arm to the cross member that sticks forward and provides a mount for the pivot that used to be on the four-cylinder Jeep engine or a bracket could be made for the Chevy engine that would provide a mounting point for the linkage. Use of our #RAGM release arm will now work with the four-cylinder linkage if a new adjustable length push rod is made up.

The clutch linkage can now be hooked up. Although this linkage will remain nearly stock, install our clutch tube spacer (included with our "C Kits") in the side of the transfer case. This will make up for the distance the transfer case was moved sideways. Drill a new set of bolt holes ahead of the original in the frame for the clutch tube bracket. Measuring the clutch pivot tube will reveal that the two arms are different lengths. Use the longer of the two arms to operate the clutch release fork. If using the #RAV6 release fork, lengthen the adjuster end of the stock pull cable and use the original clevis adjuster. If using a shortened Chevy V8 release fork, make up a new pull rod of the proper length, preferably with rod end bearings (these rod end bearings are listed in our catalog). The rod end bearings seen in Fig. 3 greatly reduce friction in the linkage. Also refer to our Guide to Clutches, Linkages & Bellhousings.

Throttle Linkage
Throttle "linkage" is most easily accomplished by using a cable and pedal assembly from nearly any GM car built after 1970. While the pedal itself may vary, all brackets and cables are very similar and are widely adaptable to nearly any GM engine conversion application.

We advise the use of the block hugging headers or manifolds. Exhaust routing is most sensibly done with a Y-pipe, and then running a larger single pipe inside the frame and then out the back on the driver's side.

Exhaust
A tight fitting, block hugging style manifold or header is recommended for clearance of steering components. Fenderwell exit headers are a solution, but sometimes a sloppy one - not to mention the vortex of exhaust fumes that they often cause to swirl into the passenger compartment of the Jeep. It is best to run the exhaust through a Y-Pipe and run it out the back of the Jeep along the inner side of the driver's side frame rail. Leave clearance for brake and electrical lines.

Electrical
Electrical changes are simple and consist of eliminating the Jeep starter relay as the Chevy relay is part of the starter and uses the same wiring connection. The Chevy alternator can be wired into the Jeep system – or the Jeep alternator can be adapted to the Chevy engine. Use the Jeep oil and temperature senders in the Chevy engine, or convert to mechanical gages. See our Guide to Electrical

Conclusion
Refer to our general information regarding bellhousing alignment, clutch, and cooling, which are relative to these engine swaps.