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1991 Jeep Wrangler Hemi - Project Old School

Posted in How To on February 20, 2007
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While we didn't get any photos of our YJ sitting forlornly in the field, here it is shortly after being rolled in the shop with the frontend and rearend removed.

As we drove through our town of Wellsville, Utah, we kept passing by a lonely '91 Jeep YJ Wrangler sitting in a field. We finally couldn't resist and stopped to speak with the owner, who told us he had purchased it for the transfer case and didn't much care about the Jeep. So, after some negotiating, we traded a .44 Magnum revolver for it and took possession. The body had just a little surface rust, although the windshield frame was pretty far gone. Once we removed the windshield, we found that the steel dash had rusted too. The 4.0-liter six and AX15 five-speed tranny had 150,000 miles on them. Our new/old Wrangler needed some work.

We decided to build this YJ the old-fashioned, "old-school" way - by doing the project ourselves in a friend's shop building behind his house in Wellsville, Utah. That friend is Eric Maughan, who's built many Jeeps, light-duty trucks, and semi tractors for fun over the years. Eric is a great welder and is one of those people who doesn't see obstacles when something needs to be overcome or designed during a project. An example of this is our leaf-spring setup. We wanted to retain the old-school spring-under design on this YJ and went to Deaver Spring for a set of excellent, supple nine-leaf packs. We were thinking of ways to flop the U-bolts to get the threads out of harm's way when Eric came up with a simple, elegant solution (see photo 9).

Lots of parts on our YJ were worn out, ripped, or broken. 4 Wheel Drive Hardware is the one-stop shop for everything we need to build our Wrangler better than it was when new. From weatherstripping to new fenders, hood, and windshield, 4 Wheel Drive Hardware has it. We also plan on installing a pair of 4 Wheel Drive Hardware Super Seats. You're probably familiar with them. They look like an old Recaro design, recline, and have a removable headrest. They're inexpensive too. We sold the hardtop and doors to make way for a Mopar YJ soft top and hard half-doors. We also have a set of soft half-doors and a bikini top from Bestop to use when the weather is nice.

The 4.0-liter six and AX15 worked well, even with 150,000 miles on them. The Toy Shop built our last 4L60E for us and it has worked flawlessly, so we figured we'd install another Toy Shop 4L60E automatic behind the 4.0-liter, courtesy of a new Advance Adapters adapter and a Compushift stand-alone transmission controller, also supplied by Advance Adapters. We were then told by our friends at Mopar Performance about their new 5.7-liter Hemi V8. We told them that trying to put a drive-by-wire Hemi in an old YJ wasn't on our list of must-dos. Then, they told us about their new 5.7 MPI Hemi. This one is designed to run in older, non-computer-controlled vehicles. It has a new, great-looking aluminum intake manifold, and the throttle body for the multipoint fuel injection accepts Mopar air cleaners from earlier days. A normal throttle cable is used. The Hemi is stand-alone and comes with its own computer (ECM). We quickly amended our must-do list and procured one of these new V8s.

Now topless, it's easy to see that our interior needs some help from 4 Wheel Drive Hardware.

The Hemi works with Mopar "A"-pattern bellhousings that include the strong and reliable 727 TorqueFlite three-speed automatic. We wanted overdrive, so we looked at the A518, essentially a 727 with an overdrive that came in late-80s to early-90s Dodge vans and trucks. This transmission is just about as long as a 4L60E with an Atlas - all by itself! Obviously, too long for our application. Advance Adapters offers an adapter to run the 4L60E/700R4 behind the Hemi. We already had that tranny, so, problem solved. As mentioned, both the Hemi and the 4L60E have their own stand-alone computers, so they should work well in Old School along with a 3.8:1 Atlas transfer case.

Once we removed the windshield, trouble appeared. The metal dash had completely rusted away in places.

Currie Enterprises has offered its RockJock 60s with aluminum third members for a few years now. The company's just introduced its new IronJock 60s, which are identical to the RockJocks except for a cast-iron centersection. We're installing a pair of IronJocks in our YJ. We'll also be using 5.13 Precision Gear gears and Detroit Lockers front and rear. The IronJock frontend comes with F-450 outers, so it's super-strong. It also allows us to use high-steer crossover steering. PSC Motorsports sent us one of its hydraulic ram-assist steering systems with a new steering box, pump, etc. Parts Mike is supplying a hydroboost brake booster and other steering parts we'll tell you about later. Mountain Off-Road Enterprises is supplying shock mounts and spring pads.

A little action with the wheel cleaned up the body tub and revealed the rust hadn't gone through past the dashpanel.

The IronJock 60 rearend hits the gas tank as it travels up and back (remember spring shackles?), so we're going to be installing a new Crawler Extreme aluminum tank from Gen-Right Off Road. The tank allows 4 inches of additional clearance, great for those like us who are installing 60s or those who want to stretch their wheelbase a bit, or both. It also comes with its own beefy steel skidplate.

36x13.50-16LT Interco Irok bias-ply tires are already mounted on 16x10 Mickey Thompson Classic II alloy wheels with OMF beadlocks. We always used 10-inch wheels for stability in the "old" days, so we wanted to return to them with this project. The Iroks have proven to be one of the very best off-road tires available today. They work unbelievably well in mud, snow, dirt, and rocks. They even work on the pavement! The Iroks will be kept on the rims by OMF beadlocks that are race-proven and also Off-Road-magazine-proven.

Follow along in upcoming issues as we build Project Old School. We think it's going to be quite a Jeep when it's finished. And, it's going to be quite a Jeep using old-school suspension design and a new-school powertrain.

PhotosView Slideshow
PhotosView Slideshow


Precision Gear
Suwanee, GA 30024
Advance Adapters
Paso Robles, CA 93446
Walker Evans Racing
Riverside, CA 92516
4 Wheel Drive Hardware
wef, AK
PSC Motorsports
Azle, TX 76020
Deaver Spring
Santa Ana, CA 92701
Tuffy Security Products
Eaton/Detroit Locker
Gen-Right Off Road
OMF Performance Products
Interco Tire Corp.
Rayne, LA 70578-0486
Toy Shop Transmissions
Pomona, Ca 91766
West Motor Co.
Preston, ID 83263
Parts Mike Parts
Don's Professional Collision Repair
Millville, UT
Mountain Off-Road Ent. (MORE)

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