The square-body Chevy trucks from 1973 to 1987 are quite popular these days. The military CUCV versions are downright drool worthy with their Dana 60 and 14-bolt axles. We have had a few in the past. Our most recent one, a 1986 Chevy K30 we call the Alabama Army Truck (http://www.fourwheeler.com/project-vehicles/1312-1986-chevy-k30-alabama-army-truck-part-1), has been sitting for a while. But recently we got it back up and running and made it bigger and badder than ever.
One major upgrade was the suspension. The AAT started out with tried and true leaf springs, but looking for better ride quality, more articulation, and additional axle control we contacted Offroad Design for its five-link and coilover shock suspension conversion. This kit is designed for pickups, Blazers, and Suburbans from 1967 to 1987 (and some to 1991) with the solid front axles.
When we first built the truck back in 2013 we swapped out the tired flat springs for a 6-inch suspension lift from Skyjacker. This was a great first step to clearing bigger tires and getting us down the trail. Two items we did back then was add the Offroad Design (ORD) crossover steering draglink and steering box brace. These important upgrades are needed for our new suspension system because we are changing to a four-link with track bar.
Our CUCV truck went under the knife and received a modified version of the kit because we also added AxleTech Portal gear boxes to the front and rear 1-ton axles. This gave us additional ground clearance and gearing, and required a suspension that could control the leverage of the portals. The new suspension requires cutting, welding, lots of grinding, and a fair bit of fabrication knowhow, but it gave the old square-body a massive new outlook on the trail. If the portals don’t allow us to clear obstacles, the new linked front will allow us to flex over them.
You can see the whole project on an episode of Dirt Every Day (watch the Alaskan Army Truck Adventure on youtube.com), but we wanted to show you some details of the new suspension here.
When it was time to go to stage two of the AAT, we opted to go big. The truck was fun on 37s, so we figured it would be great on 42s! To get gearing for the big tires and add ground clearance, we upgraded our Dana 60 and 14-bolt with a set of AxleTech portal wheel ends (driver’s side only installed in this photo). These geared wheel hub s add 5 inches of ground clearance and multiply the gear ratio by 1.5:1. So our 4.56 gears now equate to 6.84s!
The ORD link suspension requires cutting off all the old suspension mounts from the front Dana 60 and installing new mounts. Because we are getting portals, which add considerable leverage to the front suspension, ORD modified our mounts for more link separation at the axle, but the basic kit welds on the same way.
Under the engine we installed the ORD crossmember with integrated motor mounts. We will show you more of the engine swap in another article. The heavy-duty crossmember strengthens the frame and has mounts for older small- and big-block engines, as well as new big-block engines. Plus, it gives additional axle clearance at full suspension compression over the bulkier old crossmember.
While we were upgrading the suspension we also replaced the worn-out body mounts with new polyurethane mounts from Daystar. Note the frame-side body mount.
When we installed the ORD frame-side suspension mounts and tacked them in place we realized that the frame portion of that body mount would need trimming to clear the upper suspension link at full compression. A plasma cutter and grinder make short work of this job. The upper link mounts outside the frame, the lower link below the frame.
The goal of any track-bar-type suspension is to keep the track bar parallel and of equal length to the drag link, as well as keeping it as long and flat as possible. This minimizes the axle’s side-to-side movement during suspension cycling. The ORD track bar frame mount is beefy and designed to clear all the steering at full compression and full steering lock. Remember to only tack all your parts to the frame, and test cycle the suspension before you burn it into place for good.
When building a custom suspension we always recommend doing the majority of the work with the axle at full compression—or where you want full compression to be. This ensures that the axle will clear in an “Oh drat!” situation when you come off a jump or hit a massive ditch and the suspension fully compresses. We bolted the lower shock bolt of our Fox 2 1/2-inch coil over into place and put the axle at “full bump” to determine where the shock tower should go.
Luckily we were doing an engine swap the same time we were building the suspension, so we had plenty of room to move around in the engine bay. Stephen Watson, proprietor of ORD, stopped in to help with the install. After we trimmed the inner fenderwell he estimated the perfect spot for the shock and tower to clear the steering column and brake lines.
The shock tower on the driver side is the most difficult because it must clear the most obstacles. We wanted the shocks to clear the frame, steering, brakes, and tires under articulation, and preferably to stand straight up or slightly inward. One we were satisfied with the driver side we duplicated it on the passenger side for angle and location. By this point we had dropped the 8.1L big-block in place to ensure clearances (more on that in a future story).
The shock towers were reinforced with a crossover tube. This tube needs to clear the engine intake and fit under the hood of the truck. The ORD kit includes tube clamps that weld in but allow the tube to be removed in case you need to take the engine out someday.
The front track bar required an ever-so-slight bend to clear the Currie diff cover at full stuff. We prefer a straight bar, but this heavy-wall tubing should be fine. We installed the bent tube at full compression, then lowered the axle to our ride height (about 40 percent of shock travel) and centered the axle under the frame. Then we cut the remaining tube to length so that the weld-in bung and rod end lined up with the frame mount. The tie rod is still adjustable if need be, but only in full turn increments because of the bend.
We pulled the big-block out one last time to finalize the shock towers. We added another drop gusset in the middle right above the crossmember and engine mount for more strength and then welded, primered, and painted everything. We checked the brake hard lines, the fuel lines, and the wiring (all were in good shape) since they would be harder to reach after the big-block went back in.
The front axle was welded up with all the ORD brackets and bombed with a generic army-green color to fit the part under the truck. When it was dry it was time to swing it all back into place for reassembly.
The links on our kit were massive 2x0.250-wall tubes with Johnny Joints at one end and rod ends at the frame side. The brackets are all 1/4-inch thick as well, making the kit heavy but strong, perfect for our big truck. The 14-inch-travel Fox coilovers are set to run 6 inches of uptravel. A pair of Daystar polyurethane bumpstops keeps everything from crashing at full stuff.
The four-link suspension on our truck is nearly identical to that system offered from ORD for a straight axle, just slightly modified to control the portal axles. This kit works from stock height trucks up to about 12 inches of lift. We have run this same Offroad Design suspension for many years on our Ultimate Adventure trucks, and it really works well.
To match the new front suspension, we tried something unusual in the rear. We used a shackle flip kit from ORD but also did a spring-under conversion with Skyjacker 6-inch lift springs and some new U-bolts from Fabworx Off-Road. The shackle flip raises the truck 2 1/2 inches. We ran shackles slightly longer than stock, but then by moving the spring under the axle we resulted in a lift that wasn’t massive.
The rear suspension math is kind of tricky. We lifted the truck by doing the shackle reversal and using a long shackle, but then did a spring-under axle conversion to help control the leverage of the portals. However, the portals also lift the vehicle relative to the ground. All this resulted in about 7 inches of lift, plenty to clear 42-inch Maxxis Trepador tires with some trimming.
We added an Artec rear axle truss to the GM 14-bolt for two reasons. First, it ties both axletubes together, making it stronger against the twisting that is a very real possibility with the portal boxes on the end. Second, we are one step closer to being able to link the rear suspension if we decide the leaves don’t work as desired.
We buttoned up the rear suspension with a set of 14-inch Fox 2.5 shocks. We opted for 14s that could also be coilovers if down the road we decide to link the rear axle. We didn’t want to come through the bed, so we leaned the shocks back a fair bit to fit under the body. It isn’t optimal for damping, but it works. The upper shock mount is a Synergy Manufacturing shock tower we cut and welded to the outside of the frame.
How Does It Work?
After we finished the Army Truck we shipped it to Alaska for an adventure that we filmed for Dirt Every Day
(just search for “Alaskan Army Truck Adventure” on YouTube). The suspension worked great. We had no wheelhop, and the truck flexed very well. If anything, we may actually add a sway bar to keep it more stable in high-speed cornering. Overall we are very pleased with the new setup.
Fabworx Off Road