There's some incredibly challenging terrain in the state of Missouri. Much of it is concealed by seemingly impenetrable thick woods, but it's there. To traverse this environment, locals build go-anywhere machines that are rock-, mud-, and hill-friendly.
An example of one of these rigs is Mineral Point, Missouri resident Chris Harbinson's '99 Jeep TJ. In many ways, it's typical of a built TJ. It has V-8 power, a crawly transfer case, stout axles, and a flexy suspension. However, this machine, built mostly by Duncan's 4x4 of Doe Run, Missouri, has an interesting collection of components that make it unique.
We had the opportunity to see Harbinson's rig in action at the Washita ATV/MX/Jeep Park and Trails near Farmington, Missouri. The TJ adroitly and routinely negotiated a wide variety of obstacles with ease. Here's the rundown of what's lurking under the TJ sheetmetal.
Specifications
General
Owner/Hometown: Chris Harbinson/Mineral Point, Missouri
Vehicle/Model: 1999 Jeep Wrangler
Estimated value: $60,000
Engine
Type: Chevy 383ci V-8
Aspiration: Fuel injection, Gibson headers, Flowmaster mufflers
Output, hp/torque (estimated): 420/435
Drivetrain
Transmission: TH350
Transfer Case: Atlas 4.3:1
Suspension
Front: Custom 3-link, Fox 2.5 air shocks
Rear: Custom 3-link, coil springs, BDS shocks
Axles/Differentials
Front: Ford Dana 60, Chevy axletubes, Yukon Gear & Axle alloy axleshafts, OX-USA axlejoints, Ford disc brakes/modified Detroit Electrac
Rear: Sterling 10.25-inch, Dodge disc brakes/Detroit Locker
Ring and pinion: Randy's Ring & Pinion 5.13:1
Wheels/Tires
Wheels: 16.5x12 Stazworks double beadlocks
Tires: 44x18.50-16.5 Interco Super Swamper TSL
 Under the hood is a 383ci...  Under the hood is a 383ci Chevy V-8. The folks at Midwest Engines in Cape Girardeau did all the machine work and the engine was designed to generate its horsepower and torque at low rpm. It creates an estimated 420 horsepower and 435 lb-ft of torque at only 2,200 rpm. The engine features JE pistons; a Comp Cams roller camshaft, triple valvesprings and roller rockers; Gibson headers; and Flowmaster mufflers. All of the custom wiring was made by J.R. Robbs in Lesterville. Bolted to the powerplant is a TH350 transmission with a Precision Industries torque converter. The transmission has an auxiliary cooler and a B&M shifter. |  Up front, there's a Duncan's...  Up front, there's a Duncan's 4x4-fabbed front axle that has a high-pinion Ford Dana 60 centersection with 5.13:1 Randy's Ring & Pinion gears and a permanently locked Detroit Electrac differential. Chevy axletubes house a pair of tough Yukon Gear & Axle alloy axleshafts fitted with durable OX-USA axlejoints. Reinforced Ford knuckles mount Ford brakes with dual-piston calipers to rein in the forward velocity of the Jeep. This hybrid axle has a high-mount steering setup and a hydraulic-assist steering system that includes a PSC steering box and an AGR Rock Ram cylinder. The tie rod and drag link are both made from 11/4-inch-diameter, 0.250-inch-wall DOM material. Duncan's 4x4 also designed and built the custom suspension that generates 14 inches of travel and consists of a three-link setup with Fox 2.5 air shocks on custom mounts. The lower links are made from 2-inch-diameter, 0.380-inch-wall DOM tubing, while the upper link and track bar are made from 2-inch-diameter, 0.250-inch-wall DOM tubing. |  A pair of custom driveshafts...  A pair of custom driveshafts with 1350 U-joints sprout from the Atlas 4.3:1 transfer case. The T-case is protected by custom skidplating. |
 The TJ has a Ford "Sterling"...  The TJ has a Ford "Sterling" 10.25-inch rear axle. This axle has been fitted with Yukon Gear & Axle 5.13:1 gears, Dodge disc brakes with four-piston calipers, and a Detroit Locker. The Duncan's 4x4-built rear suspension is a departure from the front, having only a three-link setup in common. Instead of air shocks, it uses coil springs with BDS shocks. The result is a flexy suspension that generates about 18 inches of travel. The upper and lower links are fabbed from the same material as the front links. They use polyurethane bushings at the axle and 3/4-inch Rubicon Express Super-Flex joints at the frame. The track bar is made from 2-inch-diameter, 0.250-inch-wall DOM tubing and it also has Super-Flex joints at both ends. The rear chassis has been significantly reworked and a new crossmember has been added. Other mods include upper coil spring buckets that are recessed into the frame. |  A custom six-point rollcage...  A custom six-point rollcage made from 2- and 15/8-inch-diameter, 0.120-inch-wall DOM material keeps Harbinson safe should the TJ turn turtle. The interior has few mods, but the ones it has are functional: Racing seats, RCI safety harnesses, and Rhino Linings-lined tub. |  An RCI 20-gallon aluminum...  An RCI 20-gallon aluminum fuel cell keeps the 383ci engine supplied with gasoline. The cell is mounted in the cargo area where it is protected and easy to fill. |
 A hydraulic Mile Marker H10500...  A hydraulic Mile Marker H10500 winch is bolted to a custom front bumper made from 1/4-inch steel plate. The stinger/grilleguard is made from 2-inch-diameter, 0.120-inch-wall DOM tubing. |  Typical of a good trail rig,...  Typical of a good trail rig, all the fat has been trimmed from the exterior to increase the TJs agility on the trail. This also ensures that the big 44x18.5-16.5 Swampers on 12-inch-wide Stazworks double beadlocks have ample room to travel. Duncan's 4x4 did all of the trimming and fabbing, the team at Dale Mosier Auto Body in Park Hills completed the painting, and Graphic Options in Farmington applied the graphics. The result is a rig with some very impressive approach and departure angles and it looks great, too. | |