Some folks are born into Jeeping, while others discover it later in life-one way or the other. According to Mike Shelley, he has always been a Jeeper, he just didn't know it until three years ago when his new son-in-law Justin Roose introduced him to rockcrawling. Justin even found the '75 J20 for Mike, which was purchased for only $202.38. The price just so happened to be the exact amount that the seller needed for a one-way plane ticket for his mother-in-law. Guess that's one way of getting rid of the old battle-axe. Apparently the seller did not have as good of relations with his in-laws as Mike and Justin.
The Jeep started as a long-wheelbase J20 with a tired 401. Mike and Justin did a spring-over and took the Jeep to the Rubicon. However, the schoolbus-like wheelbase made it difficult to navigate through the trail and the rear driveshaft was hashed before they had hardly even started the trip. As soon as they got home, Mike shortened the wheelbase to 110 inches to make the J-truck more maneuverable on the trail. In a similar trial-and-error fashion, other modifications were the result of other wheeling trips, like the reinforced framerails after the frame cracked around the steering box on a trip to Eldorado Canyon, and the stock Saginaw box that is tapped for hydraulic lines and gets help from a Rocklogic ram connected to the factory tie rod.
The suspension has remained relatively simple with leaf springs front and rear. The fronts use the factory main leaf with a pack from a 1-ton truck to keep them from bending. Out back, the factory springs are on top of the axles but were moved forward on the frame to shorten the wheelbase and work in conjunction with a traction bar which limits axlewrap. Rancho 5000 shocks on stock mounts handle damping at both ends.
Keeping with the strong and simple theme, an '88 Chevrolet "Six Pack" 1-ton truck donated the entire running gear currently found under the J20. The TBI 454 doesn't get the best fuel mileage, but it provides gobs of low-end torque and runs at any angle. The Chevy motor mounts and crossmember were used, although another mount was added on the transfer case to keep the torque from breaking transmission case. The engine is backed up by a TH400 three-speed automatic mated to an NP205 that uses a JB Fab twin-stick shifter and a 32-spline Ford front output shaft. This allows the use of a factory Ford yoke, which is connected to a lengthened Bronco driveshaft with a 1310 CV joint.
With a fullsize Jeep you don't need to narrow the axles or move the springs in order to run a 1-ton front axle, making the process a relatively easy one for Mike. The front Dana 60 uses a welded carrier, 5.38 gears, and a diff cover from Ruff Stuff. The rear GM 14-bolt received a little more attention, including disc brakes using Ruff Stuff brackets, a Yukon spool, matching 5.38 gears, and Great Lakes Off Road pinion and diff guards on the shaved housing.
Body and Interior
Mike added a fresh coat of red aviation paint to the J20 just before we shot our photos, but he still isn't afraid to scratch it. Starting up front, a Smittybilt bumper holds a Warn 8274 winch. The factory flares on the fenders were cut out to make room for the Pitbull tires and the hood was spaced up in the rear to let hot air from the big-block escape from the engine bay. The factory radiator is tasked with keeping the 454 cool with the help of an electric fan from a Ford Taurus. Moving to the sides of the Jeep, the rocker panels were cut for clearance and replaced with box tubing that is stitch-welded directly to the cab and frame. The doors come off in the summer to increase visibility and are replaced with bars that bolt in for added safety. In the winter the doors are put back on the Jeep to keep the cab warm during snow wheeling.
The stock heater is still present, although with the rear glass long gone the warm air does not stick around for long. The factory gauges sit in front of the stock tilt column and are adapted to the Chevy engine. Mike and his passenger sit in "cheap and comfortable" seats from a Chevy Astro van. Out back the bed was cut and rewelded to match the new wheelbase and improve the departure angle. "In retrospect I should have just built a flatbed," Mike confessed. "It would have been a lot easier." The bed holds a fullsize spare, Smittybilt rollbar, the fuel tank, and a Hi-Lift jack. The tailgate and inner fenders were ditched to save weight, but even on a diet the truck still weighs a portly 5,400 pounds. The rear bumper is sealed and serves as an air tank, that's fed by the converted York air conditioning compressor.
Good, Bad, and What It's For
The 39x16.50-16LT Pitbull Rockers provide a lot of clearance and work excellent in the rocks, sand, and snow that Mike frequents when wheeling with his son Nyle and son-in-law Justin. The only downside to the big tires is that they could benefit from a lower crawl ratio than offered by the relatively tall gearing of the TH400 and NP205. And while we agree with Mike that a flatbed might be more functional, we totally dig the shortened factory bed.
Why I Shot This Feature
I like how Mike balanced strength, simplicity, and cost with his J-truck. He didn't worry about sourcing a high-pinion front axle from a Ford or a Gen III engine from a late-model GM. He got all of the drivetrain from one vehicle and retrofitted it into a more nimble, better looking package for use on the trail. Now Mike just needs to pass the Jeep heritage on to his grandkids when they are born.
Vehicle: '75 Jeep J20
Engine: '88 Chevy TBI 454 V-8
Transmission: '88 GM TH400 three-speed automatic
Transfer Case: '88 GM NP205
Suspension: Leaf springs (front and rear)
Axles: '88 GM Dana 60 (front), '88 GM 14-bolt (rear)
Wheels: 16x10 steelie with Crawlfab beadlocks
Tires: 39.5x16.50-16LT Pitbull Rockers
Built For: Going everywhere short wheelbase Jeeps go
Estimated Cost: $6,500