Westen Champlin Builds A Wild Cummins-Swapped Kei Truck

Dropping a massive diesel engine into a tiny vehicle sounds like a recipe for disaster. However, tackling a ridiculous Cummins swap is exactly what happens when creative mechanics push the boundaries of physics. Westen Champlin and his crew decided to transform a Japanese Kei truck into a heavy-duty smoke machine by mounting a 12-valve Cummins engine straight into the bed.

Applying Redneck Science

Before making any permanent cuts, the team ran into a major hurdle regarding drivetrain rotation. Because the heavy diesel engine sits backward, the output shaft spins the wrong way for forward movement. The crew utilized some unorthodox testing methods by physically rolling an inverted Jeep to study axle rotation. Champlin explained: “So, we’re going to flip a car upside down so we can see which way it goes after it’s upside down.” This bold experiment proved that mounting the tiny differential upside down easily fixes the directional problem.

Prepping For The Cummins Swap

Once the mechanical theory checked out, the crew shifted its focus to aesthetics because the camouflage hunting theme clashed with a performance build. Professional body shops quoted thousands of dollars, so the team grabbed cheap sandpaper and primer from an auto parts store to tackle the job itself. It spent a few hundred bucks and transformed the tiny truck into a bright red race machine. The visual transformation perfectly set the stage for the heavy lifting.

Zip Ties And Big Boost

Getting the heavy powertrain securely mounted required cutting a massive hole straight through the freshly painted bed. After removing the factory motor, it carefully lowered the 12-valve diesel alongside its transmission and transfer case into the back. Putting everything together involved fabricating custom intercooler mounts and running electrical wiring to a ratchet-strapped battery tray. Champlin noted: “I don’t want to get you too excited here, but we have officially Cummins-swapped the K truck.” The engine fired right up and pushed thick diesel smoke everywhere.

Taking Flight And Breaking Parts

Taking a top-heavy rig for a test drive naturally led to destructive choices. The crew successfully popped a massive wheelie before a terrible metal clanking sound echoed from under the chassis. Doing stunts completely destroyed the transfer case and left the truck stuck without any usable gears. Even with the mechanical carnage, turning a slow utility vehicle into an aggressive torque monster proved incredibly entertaining. Pulling off this wild Cummins swap shows exactly what happens when crazy fabrication ideas become reality.