Stock Willys truck frames are incredibly flexible. We like our flex to come from the springs, so we cut 11/48-inch plate to fully box the frame from front to back. We found once the shackles were installed they hit the underside of the framerail, so we severed a piece of rectangular tubing and notched the framerail, as shown, to allow the shackle to clear. | 
To extend the front framehorns, we hacked and chopped the vintage Ramsey PTO winch bumper that came on the truck. Once elements of the bumper were bolted, welded, boxed, and reinforced to the frame, we installed the Rancho 2.5-inch lift Wagoneer springs (PN 44044) and mounted the M.O.R.E. stubby spring perches to the front of the frame. We added a tube in between the mounts for rigidity and folded the side of the mounts in for reinforcement. The 47-inch long Ranchos have an offset centerpin, with 22.5-inches between the spring mount and the axle centerline and 24.5 inches from the shackle to the axle centerline. |
With the front springs hung, we modified a Dynatrac high clearance U-bolt flip kit (PN DA60-2X5796-B) to work with our high-pinion Currie Rock Jock Dana 60 and hung the axle under the frame. We also removed the engine and were greeted with lots of unwanted frame flex because a previous owner had hacked out the factory front crossmember. | 
Without the engine acting as a crossmember, it was impossible to get correct measurements to build the rear suspension because the framerails were now back out of square. We put the suspension on hold for a weekend while we built a full interior cage of 131/44-inch, 0.120-wall DOM tied solidly to the frame. Eventually, the cage will extend forward through the engine compartment and back into the bed, but that'll come later. |
Once we put five 100-pound sand bags on the front to simulate an engine, we discovered the rear was going to be way too high if we used the regular M.O.R.E. spring hangers. Rather than exchanging our pieces for the company's stubby versions that we used in the front, we cut and welded the standard hangers to lower the rear. | 
With the hangers built, we measured the centerline of the hangers and the frame in several places. Then we drew a line through our measurements and eyeballed the hanger onto the frame. Once tack welded, we installed the rear spring and rotated it up to make sure it contacted the frame in the center. You need to take a little time to ensure the hangers are square so the spring bushings don't bind and get chewed up as the suspension cycles. |
The cage alleviated some of the flex, but we could still grab the forward framehorn and severely tweak the frame out of shape. These pickups have five factory crossmembers, not counting the tranny/T-case crossmember. We found our No. 3 and No. 4 crossmembers were totally rusted through, so we built new ones out of some 2x3-inch, 0.120-wall rectangular tubing. The new pieces did the trick, making the frame totally solid. | 
For the rear shackle hangers, we determined where we wanted the shackles to hang with the springs at full droop and used a 131/44-inch hole saw to buzz through the boxed frame. Then we cut a piece of 131/44-inch, 0.120-wall DOM tubing and slid in some 1.5-inch diameter Wrangler spring bushings. We assembled the shackles on the spring, then tacked the tube to the frame before pulling it apart and welding it up. |
For the rear springs, we ordered some 52-inch Rancho springs (PN RS86209) intended for the rear of a fullsize Chevy. We removed the overload spring and flipped the centerpin, then mounted them to our 14-bolt using Dynatrac's high-clearance U-bolt kit. | 
The 4-inch lift RS86209 springs have a light 287 lb-in spring rate, which settled a bit more than we were expecting. However, once we add the drivetrain and a winch to the front of the vehicle, we're expecting the stance to even out. If we need to, we'll fine tune the suspension height with some longer shackles on the front or rear, as needed. We also discovered the bed floor we thought was diamond-plate aluminum is actually a 4x8-foot sheet of 31/416-inch galvanized steel, so replacing it with expanded steel will probably shave 400 pounds from the bed. |