The 1986 Chevy truck I built three years ago has been sitting idle a few years now. The K30 square-body, referred to as the Alabama Army Truck, had gotten a 550hp supercharged Chevy 6.2L crate engine, but then that engine was robbed for my Jeep, along with the transmission. And then the truck got mothballed. But readers of 4WOR and viewers of Dirt Every Day have been asking for it back, so I decided I would rebuild it bigger than ever. I had just two weeks to make the work happen for an upcoming Dirt Every Day episode, so I called everybody I thought might want to work on it and begged them to come help, and we knocked the build out of the park.
The old engine was impressive but very expensive. This time I opted for a used 8.1L big-block Chevy from a 3/4-ton Suburban for good power on a budget. I also wanted to run the new 42-inch Trepador tires from Maxxis and have enough gearing to make them work, not to mention rehash the entire suspension. It wasn’t the easiest build, but it came together quickly and resulted in a truck that is fun to wheel and worked better than expected. You can see it all on an upcoming episode of Dirt Every Day on YouTube. Here is a behind-the-scenes look at how it went down. We’ll show you more on the 8.1L engine swap and suspension build in future issues of 4WOR.
This 1986 Chevrolet K30 is a military CUCV truck. This is actually the second truck like this I’ve owned, the first having been stolen in 2009. I built this one in 2013 in Alabama, thus the name Alabama Army Truck. In that build I added a supercharged LSA engine with 550 hp and Detroit Lockers to both axles with a 6-inch Skyjacker suspension to clear 38s. I drove it like this for a while but then decided I wanted that engine in my Jeep. I parked the truck on some little rollers and thought about selling the carcass, but that seemed wrong. As the square-bodies got more popular, I decided it was time to rebuild it.
Everyone told me to do a Cummins diesel swap, but I already had a Cummins in a few other trucks, so even though those are great engines I opted for something a bit different. The late-model 8.1L Chevy big-blocks are easy to find and pretty inexpensive for the power they make. I found a 325hp/445 lb-ft version from a 2004 Suburban and brought it home cheap! Then I stripped off the engine wiring harness and sent it to Tilden Motorsports to be redone and have the ECU reflashed.
I wanted to try something different with the Chevy axles, namely portals. I have put Axletech portals on vehicles before, and they are great for strength and ground clearance. The portals bolt on the front with no special fabrication needed.
No special fabrication is needed to install the portals to the axle, but we did do some special fabrication to install the axle in the truck. The stock front leaf springs were replaced with a five-link front suspension from Offroad Design. The reason for a linked suspension was to help control the additional leverage of the portal boxes and bigger tires. I also replaced the body mounts with new polyurethane mounts from Daystar.
I kept the rear suspension leaf sprung, but I swapped from spring-over to spring-under in an attempt to control axlewrap with the portals. I lost some ground clearance, but I was happy with the performance of the spring under with a set of Fox shocks. I got my spring perches from Fabworx and added an axle truss from Artec to tie both axletubes together. The thick steel plate replaces the axle spindles of the 14-bolt, which is where the portals bolt on.
With the additional 1.5:1 gearing of the portals along with the 4.56 ring-and-pinion, I now have a final axle ratio of 6.84:1. To deal with that, I upgraded to an automatic overdrive from Gearstar Transmissions. The 4L80 came with the big-block, but I sent it to Gearstar to be rebuilt and dyno’d. The result is a transmission with grunt for wheeling and overdrive gearing for highway cruising.
The reason for the rebuild was twofold. I wanted my big truck back on the road, but I also wanted to clear a set of these new Maxxis 42-inch Trepador tires. The Raceline wheels have lots of backspacing to make up for the width of the portals, and the tires are over 42 inches tall for even more ground clearance. The truck is bigger than ever and so we decided to take it to the biggest state in the nation for an adventure.
Tune into Dirt Every Day to see how we renamed the truck the Alaskan Army Truck. We will dive into more of this build in detail in future issues.