This Homegrown 1973 GMC Jimmy is One Sweet Ride

jimmyAs rumor has it, in 2007, two really good friends and avid off road enthusiasts were sitting in the middle of a dry lake bed somewhere near Johnson Valley, California enjoying a few cold ones. The talked about what a cool place this area would be to hold some sort of off-road racing event. The conundrum facing these two friends were just what type of event would they put on if they could organize such an event?

K5_015There was a bit of debate concerning this subject as friend one, as we will call him, was very much into the high horsepower, Trophy Truck type race vehicle and therefore, was in favor of an all out dessert race – go as fast as you can from point A to point B. Friend two, meanwhile, was more into the technical aspects involved with the sport of rock crawling. His vote was to hold a rock crawling event that would be one of the most difficult, and technically challenging events that even the most seasoned crawler would drool over. 

K5_005After consuming several more cold ones, the guys decided the only logical solution was to do an event that combined the two disciplines, and so was born the event known today as the King of the Hammers, one of the largest and most popular off-road events that take place in North America.

Every year, thousands of off-road enthusiasts converge on the Means Dry Lake at Johnson Valley, California to enjoy this one of a kind event. In 2015, over fifty-thousand avid off-road race fans occupied what is known as Hammertown.

K5_026One of the perks to attending this event is that in addition to taking in the race action, there are off-road vehicles everywhere you look. It’s like attending an impromptu mega display of custom and vintage off-road vehicles.

All you have to do to enjoy this part of the event is roam through Hammertown and enjoy the sights. We at Off Road Extreme did just that, and we came across this homegrown 1973 GMC Jimmy K30 that sparked our interest. Naturally, we stopped to check it out.

K5_017The truck belongs to and is the creation of Steve Davis. Davis hails from Olancha, California, located in the Owens Valley on the Eastern slopes of the Sierra-Nevada mountain range. Davis is a 34-year veteran firefighter/paramedic and is currently working as the district chief for the Olancha fire department. He is a lifelong off-road enthusiast, and gives credit to his Dad for his love of the sport. “I got really interested when I was about 12 years old,” Davis recalls. “The first 4×4 vehicle I remember in the family was the 1967 Nissan Patrol that Dad drove.”


The custom K30 badges look like they came from the factory.

Over the years Davis has owned and driven a number of different 4×4 vehicles: Land Rovers, Fords, and of course, the early-model square-bodied GM trucks.

“I’ve had a number of different vehicles, but I always seem to gravitate back to the GM products,” Davis explained. “I’m comfortable with them, I know how to work on them, parts are readily available, I mean, I’ve driven a GM product of some sort since high school.”


Hey, you never know when you might need one of these!

In 2002, Davis began the build on his 1973 Jimmy. At the time, Davis owned a company that provided off-road rescue and recovery for various desert racing events, including motorcycles.

“It just seemed like a good fit for what I was doing at the time,” Davis said. The pretty yellow Jimmy actually began life as a 1973 Suburban that Davis had purchased for a cool thousand dollars.

Thinking this would be the foundation for his off-road rescue and recovery vehicle, Davis quickly discovered the Suburban had an unbuildable motor and more rust than he cared to deal with. “The good news through all of this was that it had good axles under it, and a few other parts I could build on,” he said. After some thoughtful consideration, Davis began to rethink this project: “I decided a Suburban was just too big for what I had in mind, and I was thinking a Jimmy would make a better choice, so I cut the frame down, bought a tub out of an old Blazer, and started building from there.” 

K5_080For the next five years, Davis, with help from a few friends and neighbors, transformed the old Suburban chassis into a full leaf-sprung truck with a 350 ci small block Chevy, a Turbo 400 transmission, and an NP205 transfer case. The front axle was a Dana 44, and a Corporate 14-bolt Detroit locker sat in the back.

Although the truck performed well, it did not meet the expectations of its owner. “The thing rode terrible,” Davis recalled. “I had sold the rescue and recovery business, so I wanted to go more to a vehicle I could use for daily or recreational use.”

A look under the truck reveals the 63-inch leaf springs in the rear, as well as the custom designed and fabricated transfer case skid plate.

With this in mind, Davis pulled the truck back into the friendly confines of his two-car garage, and began to make a number of changes and improvements to make his truck a bit more user-friendly.

K5_110This rebuild took a little over two years, and some of the improvements included replacing the Dana 44 front axle with a newer Dana 60, while the 350 small block gave way to a 454 big block. Davis also installed 52-inch leaf springs with a Detroit Tru Trac limited-slip differential under the front of the truck. These changes greatly improved the ride and handling characteristics of the truck, but, as is common with this sort of thing, the build never seems to end; there’s always something that could be done to make it better.


Davis included tow hooks, and a winch, just in case he might need them.

The truck remained in this configuration until 2010, when Davis happened to meet Brian Hays and Glen Westberg. Hays and Westberg were (and still are) very involved with the design and fabrication of off-road vehicles, and are known as very accomplished engineers and machinists.

Hays and Westberg had built a number of vehicles including several Jimmys similar to the truck owned by Davis. “The trucks these guys had built were just awesome,” Davis affirmed. “They had four-link suspension and Cummins power, but after seeing what they were doing, I knew exactly what I wanted to do.”


Davis says he’s okay with getting out of the truck to engage the hubs.

Hays and Westberg agreed to help and advise Davis with his planned rebuild, suggesting a complete frame-off restoration and rebuild. Davis returned home, put his truck back in his two-car garage, and took it down to the bare frame. This was done in preparation for what he intended as the final build on his yellow Jimmy.

”Without the help and advice from Hays and Westberg, I would have never been able to complete the build on my own,” Davis explained. “The entire process took a little over two years to complete, and the finished product is what it is today.” 


Today, the truck sits on a modified GM frame with additional custom-fabricated crossmembers in the front, as well as a specially-designed and fabricated crossmember and skid plate for the transfer case. Front suspension is a custom-fabricated four-link system by DP Performance. Front Shocks are 16-inch FOA remote reservoir coilovers with 300/150 springs and a Dana 60 front axle with  4.56 gears. Rear suspension is comprised of 63-inch late model GM leaf springs with flipped shackles from Off Road Design. 16-inch FOA remote reservoir shocks and a 14-bolt late model GM axle with 4.56 gears round it out.

Both drive axles are equipped with Detroit Lockers for getting the most traction possible. Front brakes are Standard GM single piston 11-inch discs, with Howe dual piston calipers over 11-inch discs on the rear. A PSC, ported, Ram Assist steering box takes care of the directional duties, and the truck sits on 9.75 X 16.5 Centerline aluminum wheels with custom fabricated Coyote rock rings. The wheels are wrapped with BFGoodrich Mud Terrain 37×12.50R16.5 rubber.


The 454 big block fits snugly between the fender wells, and the foam K7N filter keeps the sand out of the Pro Form carburetor.

The horsepower is supplied with a 1996 sixth-generation 454 ci iron GM big block engine with stock steel heads and stock GM hydraulic valves. The bottom end is stacked with steel crankshafts, journals, connecting rods, and flat-top pistons. The camshaft has a 218/228 lift with a .500/.500 duration, made by Edelbrock

Next up, the intake manifold is an Edelbrock Air Gap with a Pro Form 750 CFM carburetor feeding the horses, which eventually leads to a set of 2.5-inch Hedman headers with a custom designed and hand bent 2.5-inch steel exhaust by T&T Mufflers. The noise is maintained at acceptable levels with a set of Pypes Street Pro Mufflers, while a Davis Unified Ignition system lights it all up.

The truck looks good from any angle.

A GM Turbo-Hydramatic 700R4 transmission equipped with a Red Eagle clutch package and 1800 stall converter moves the power to the Atlas II transfer case. Ford one-ton driveshafts move the power to the axles. The 700R4 is also equipped with a Transgo shift kit and Art Carr racing shifter.

The interior remains stock with a few upgrades.

The exterior features front and rear custom-fabricated brush guards and bumpers. A stock GM sliding rear window, multiple Highlander Series light bars, front winch, hard shell bed cover, custom designed K30 badges, and Corvette yellow urethane enamel paint are all included. The interior is stock with the exception of the single hoop roll bar, the custom dash by American Autowire, the Pro Comp Gauges, and a Lowrance Elite 5 GPS to prevent getting lost along the way. Last but not least, the steering wheel is out of a vintage 1972 Chevelle to add some flair.

K5_005Davis admitted there were still a few changes he wanted to make to his truck: “I’m considering changing to fuel injection. The truck gets off camber from time to time, and although it has not happened yet, I know sooner or later the carburetor will flood out and leave me stranded somewhere.” Davis is also thinking about putting a four-link suspension on the rear of the truck. “I’m talking with the guys at DP Performance about this, but, you know, it’s one thing at a time,” he said.

K5_122When you look closely at this truck, it’s very easy to see the dedication and craftsmanship that went into this build. The attention to detail and the quality of the parts and pieces used to construct this truck are second to none. “I always wanted a truck like this,” Davis smiled. “As far back as I can remember, this was my vehicle of choice.” Davis is very aware that after he installs the fuel injection and the four-link system on the back, there will be very little he can do to add to or improve his favorite ride, and that’s okay. Maybe he will consider retiring the truck, and reserve it for the occasional trail ride with his lovely wife riding shotgun.

Photography by David Chick

About the author

Chuck Green

As a professional writer, and photographer Chuck has always had an affliction for anything related to motorsports. Over the years he worked events from local short tracks to the high profile series of NASCAR, Indy Car, IHRA, and NHRA.
Read My Articles

Everything Off Road in your inbox.

Build your own custom newsletter with the content you love from Off Road Xtreme, directly to your inbox, absolutely FREE!

Free WordPress Themes

We will safeguard your e-mail and only send content you request.

Off Road Xtreme - The Off Road Magazine


We'll send you the most exciting Off Road articles, news, truck features, and videos every week.

Off Road Xtreme - The Off Road Magazine


We will safeguard your e-mail and only send content you request.

Off Road Xtreme - The Off Road Magazine


Thank you for your subscription.

Subscribe to more FREE Online Magazines!

We think you might like...

Diesel Army
Diesel Army
Street Muscle Mag
Hot Rods & Muscle Cars
Engine Labs
Engine Tech

Off Road Xtreme - The Off Road Magazine

Thank you for your subscription.

Subscribe to more FREE Online Magazines!

We think you might like...

  • dieselarmy Diesel Army
  • streetmusclemag Hot Rods & Muscle Cars
  • enginelabs Engine Tech

Off Road Xtreme - The Off Road Magazine


Thank you for your subscription.

Thank you for your subscription.

Off Road Xtreme - The Off Road Magazine

Thank you for your subscription.

Thank you for your subscription.