King of the Hammers KOH Rock Buggy Build: Turning a racing 4x4 dream into reality
Written: February 09, 2011
Chris Duffin, an extreme offroad enthusiast and friend to WARN is building a rock buggy with the goal of racing it at the
King of the Hammers
Chris bought his first Jeep 4x4 pictured above, a stock 76 CJ 7
, 13 years ago when
he was in college and it was his daily driver for a few years. Knowing nothing of offroading at the time it only saw
dirt roads and the occasional outing with other inexperienced four wheelers. The only upgrade it saw at that time
was a Dana 44
front, spring over, and a set of 35's.
After moving to Portland his Jeep became a fulltime offroad vehicle. He added a Currie 9"
rear axle, lockers front and rear, 4-1 twin stick transfer case, winch,
aftermarket leaf springs, 37's and a few other goodies. He also rebuilt the
that it came outfitted with and installed a throttle body injection system on it.
The next phase of his CJ 7's development included a custom built full roll cage as well as an exo cage for the front,
extending the wheelbase, leaf packs all hand polished and tapered, etc.
At this point Chris was becoming an experienced offroader taking his Jeep to various locations and terrain in the
Northwest. With all this wear and tear, Chris decided to make other modifications, including an axle swap and transfer case
replacement. Swapping these components out started a chain reaction selling the drive lines, suspension components,
engine, etc, etc which led to his decision to build a ground up custom engineered rock buggy in his home shop/garage.
While in the process of planning his buggy build, the first King of the Hammers
race with the original 13 members was run. He instantly knew what he would be building the rock buggy for.
His rock buggy has been sitting the last two years due to work, projects, and a 2 year old.
But it is now back out of storage and the build is resuming to completion!
Here are some of the specs and link to his Pirate4x4 thread for the build. We will update you as his work progresses. Note
that all axle items were designed and manufactured by Chris, less the shafts:
Pirate4x4 Build Thread
Unimog 404 Axles from
Central tire inflation
Disc Brakes with Corvette 4 piston calipers
Integrated Portal Box Reinforcements
Cryo Treated Portal gears, Ring&Pinion, and CV's
300M axle shafts (CTM Racing)
Air actuated lockers
4 wheel steering with
POS steering system
Perfect ackerman and 45 degree steering (Front & Rear)
Custom dual shear steering mounts
18" Sway-a-Way coilovers with full travel on all 4 corners
Evolution Monster Heim Joints
FOA 2" x 4" travel air bumps on 4 corners
Currie Sway bars Front and Rear
Stak 3 Speed (custom air shifted)
Chevy 383 with an Edelbrock MPFI (currently still a 350)
Front - Warn 8274 with
9.5XP motor and Synthetic
Rear - Warn 9.0 RC
Ron Davis radiator w/Dual Spal fans and nothing
in front of it
Warn SPI compressor
Twisted Stitch heated seats
47" Interco LTB's with Staun internal beadlocks
Separate Setrab & B&M coolers for Engine Oil, Transmission and Power Steering
Filed under: ,