Some custom trucks begin with a clean survivor, a running project, or at least a complete vehicle. Chad Compton’s 1974 GMC C15 Super Custom wasn’t any of those things.
When Compton acquired the short-bed Fleetside in 2022, it was essentially a full-size jigsaw puzzle. There was no engine in the truck, the bed wasn’t mounted, body panels had been removed, and assorted parts were packed away in boxes. Three years later, that collection of pieces emerged from a literal barn as a meticulously detailed, LS-powered square body wearing a custom Sky Blue and white two-tone finish—and carrying a Best of Show – Paint award to prove just how far the project had come.
Above: Before photo (courtesy of the owner)
For Compton, an industrial designer and owner/operator of DEFI Construction, Inc., the GMC represented something more than another custom build. After years spent around precision-driven home, office, and industrial design projects for others, this was an opportunity to build a pickup truck entirely to his own standards, with control over the design, details, craftsmanship, and execution.
There was also a more personal influence behind the project.
As a teenager, Compton had envisioned undertaking a custom build with his father. Although that particular project never happened as planned, the idea stayed with him. Decades later, that influence became part of the motivation behind this GMC.
And appropriately enough, it was built at home, in his barn.
From Basket Case to Blue-Ribbon Square Body
Above: Before photo (courtesy of the owner)
Before arriving at Compton’s “Barnhouse,” the GMC had already passed through the hands of well-known square body enthusiast Rene “C10 King” Martinez and later Kyle Cooper of Orange, California. Cooper had invested substantially in parts for the project, but the truck remained unfinished when Compton took ownership.
Rather than simply assemble what was there, Compton went all the way.
Above: A true ladder frame up restoration with some good buddies helping the process along (photo courtesy of the owner)
The factory chassis was retained, but the GMC received a complete frame-off restoration. The frame was stripped, sandblasted, and powder coated. The original control arms were retained and restored. Factory hardware was refinished in black oxide, and replacement hardware was carefully standardized using black oxide, stainless steel, or Grade 8 fasteners.
Above: Nighttime cruising (photo courtesy of the owner)
That attention to detail became a theme throughout the build. The objective wasn’t merely to make the GMC look finished from a few feet away. It was to create a truck that rewarded a closer look and drove like a brand new pickup from GMC.
LS Power and 4L80 Strength
Under the hood is a refreshed 6.0-liter LQ4 LS-platform engine that keeps its stock internal configuration that benefits from incorporating a carefully selected combination of swap and supporting components.
Flowtech ceramic-coated LS exhaust manifolds feed a Hooker Blackheart 2.5-inch stainless exhaust system. A Holley LS oil pan provides the necessary chassis clearance. Camaro water-pump and front accessory components are joined by a Dirty Dingo alternator bracket and Vintage Air low-mount compressor arrangement.
Engine management is handled through a PSI Conversion harness, with a BP Automotive two-speed fan relay system taking care of cooling duties. Fuel delivery includes a Walbro 255-lph pump and Corvette-style regulator. A Mighty Mouse catch can and custom PCM mounting bracket help complete the installation.
Above: Owner supplied photo
Street Tuning & Dyno in Los Angeles handled the 91-octane calibration. Compton estimates output at approximately 340–360 horsepower with around 360 lb.-ft. of torque, which is plenty for a cruiser that was always intended to be driven.
Backing the LQ4 is a 4L80 automatic transmission equipped with a shift kit and connected to a custom driveshaft from Drive Lines Inc. Out back, the factory 12-bolt rear axle carries 3.73 gears, with a Positraction differential planned for the future.
Low, Wide, and Built to Drive
The GMC’s stance is unmistakably custom, but Compton wanted a static suspension rather than relying on air to achieve the look.
The truck sits approximately six to eight inches lower than stock. Up front, CPP 2.5-inch X-10 modular drop spindles work with three-inch MaxTrac springs and Belltech shocks. A CPP sway bar adds additional control.
Stopping performance received just as much consideration. A CPP Big Brake kit puts 13-inch brakes and Corvette hubs at the front. Stainless steel brake lines run throughout the truck.
At the rear, the stance comes courtesy of a flip kit, two-inch shackles, a C-notch, and Belltech shocks.
The suspension package puts the GMC exactly where it needs to sit over a set of Detroit Steel wheels from Mobsteel. The fronts measure 20x8 with 4.5 inches of backspacing. The rear wheels are an imposing 20x11 with 6 inches of backspacing.
Diamond Back Classics supplied the custom whitewall tires: 235/40R20s with 7/8-inch whitewalls up front and 305/35R20s with 1-inch whitewalls at the rear.
One of the best details, however, comes from the original truck. Its stainless-steel hubcaps were restored and polished by Chromadora in Santa Ana, California, with paintwork by Chris Harsh of AkzoNobel. Against the modern wheel and tire proportions, the restored factory-style caps give the GMC a distinctive combination of vintage character and contemporary stance.
Sky Blue, White, and a Lot of Blocking
If there’s one element that immediately defines Compton’s GMC, it’s the paint.
The body was stripped to bare metal before receiving epoxy primer, polyester build primer, and extensive blocking and surfacing. Aria Group in Irvine, California, completed the exterior paintwork using PPG products.
PPG 2185 White forms one half of the classic two-tone treatment, while the blue is a custom-mixed PPG Sky Blue. Waterborne basecoat was topped with solvent clear before the finish was color-sanded and buffed.
The result is a color combination that looks entirely appropriate for a 1974 GMC while being considerably more refined than anything that left the factory.
The quality of the finish didn't go unnoticed. At the 2026 I Am America show at the Anaheim Convention Center, the GMC earned Best of Show – Paint.
To help preserve all that work, the front clip received paint protection film, with ceramic protection applied to the finish.
The body contains numerous less-obvious modifications as well. Compton fabricated a custom firewall and modified the fuel filler neck so it would work properly with modern vapor-recovery fuel-pump nozzles. WamRod hood struts replace the traditional arrangement, and an LS Fab tailgate saver adds protection at the rear.
The bed is finished with color-matched Raptor liner. One particularly rare detail is the GMC embossed tailgate with its upper-left-side lettering—a piece that square body enthusiasts are likely to spot immediately.
Saddle Interior with Modern Comfort
Inside, the same philosophy continues - retain the visual character of the square body while upgrading virtually everything that affects the driving experience.
A Dakota Digital Syndicate Series VHX instrument package fills the gauge opening, accompanied by a shortened I-DIDIT Syndicate Series steering column. Vintage Air climate control makes long trips more comfortable. Dapper LED lighting modernizes illumination.
The custom upholstery is finished in dark saddle vinyl with diamond stitching and gold accent thread. LMC color-matched door panels and matching visors integrate with the color scheme. A painted metal roof ceiling remains exposed rather than being hidden beneath a headliner.
Underfoot, a TMI carpet kit and matching custom floor mats sit over Kilmat insulation.
A RetroSound HD head unit provides a period-friendly appearance with modern capability, feeding a Kicker audio system that includes a custom enclosure housing dual 10-inch subwoofers.
The end result isn't an interior designed solely for show judging. It’s a place Compton can comfortably spend hundreds of miles behind the wheel, which is exactly what he has done.
No Trailer Required
Plenty of highly detailed show trucks accumulate their mileage a few miles at a time. Compton chose a different approach.
The GMC’s maiden voyage was a roughly 700–800-mile round trip from Orange County to Avila Beach, California, for the 2025 SLO (San Luis Obispo) Down event. The trip included approximately 300 miles in each direction along with additional coastal driving.
The truck was driven to the show, not trailered.
As of the completion of the build information supplied to Classic Industries, the GMC had accumulated approximately 1,950 miles.
That may be one of the most telling details about the entire project. Beneath the show-quality paint, polished details, restored hardware, and carefully selected components is a truck intended to function as a truck, not simply occupy a display space.
It Takes More Than One Barn Builder
Although Compton was deeply involved in the hands-on construction, he is quick to recognize the people and companies who contributed their expertise.
Hands-on contributors included Alfred Dena, Ryan Turner, Chris Thatcher, Matt Marshall, and Chris Harsh alongside Compton himself.
Professional and vendor support came from Street Tuning & Dyno, Aria Group, Auto Metal Direct, Classic Performance Products, Vintage Air, Holley and Hooker Blackheart, Dirty Dingo, Detroit Steel, Diamond Back Classics, Dakota Digital, Dapper Lighting, BP Automotive, PSI Conversion, Primo Powder Coating, Specialized Powder Coating, Chromadora, Dunhan Metal, Powertron, Classic Industries, LMC Truck, Drive Lines Inc., The Car & Truck Shop in Orange, Royalty Wraps & Tint in Costa Mesa, E-One Stop in Orange, RetroSound, and Kicker Audio.
For Classic Industries enthusiasts, that parts list illustrates something familiar: a high-level build is rarely about one spectacular component. It’s the combination of hundreds of individual choices, and the care taken when putting them together, that determines the finished result.
The Barnhouse
Above and several below: How cool are these owner-supplied in-progress restoration build photographs at the owner's barnhouse?
Perhaps the most interesting part of Compton’s story is that the ’74 GMC isn't an isolated project.
The property he calls the “Barnhouse” has become the birthplace of a growing collection of builds.
Among them is a 1966 Chevrolet C10 Fleetside that originally ran a 6.0-liter truck engine before later receiving an LS3. It combines a patina exterior with a frame-off, powder-coated chassis and highly detailed engine compartment.
Another 1974 GMC square body retains its red patina and a traditional 350 small block that features a completely restored and detailed chassis underneath.
A 1973 Chevrolet C10 received an LS3 swap, as did a 1968 C10 that underwent a complete nut-and-bolt restoration. That truck combines a powder-coated frame and restored chassis with its original patina exterior, along with Buddy Seats and an upgraded interior.
The Barnhouse résumé gets even broader with a 1979 Chevrolet Malibu G-body. It too received an LS3 and frame-off powder-coated chassis while retaining its original patina exterior and interior. The Malibu eventually made its way to Texas, where it has seen dragstrip duty with nitrous.
A 1958 Chevrolet four-door coupe with a big-block engine rebuild and swap rounds out the list of projects. Private car shows and gatherings have also been hosted on the property.
Above and below: Owner supplied photos of a private car show/gathering - If you're a gearhead, the barnhouse is the place to be!
In other words, “built in a barn” isn't a clever description attached to one GMC. It has become part of Compton’s approach to the hobby.
A Personal Standard
Compton isn't formally affiliated with a truck club, although an unexpected 2025 adventure introduced him to the Kern County Crew. After winning a 1989 OBS Chevrolet pickup in a raffle at the Las Vegas Grand National Truck Show, he traveled to Kern County to collect it and joined the group for the drive back to Orange County, an experience later shared by the crew on social media.
Yet the Sky-Blue GMC remains a particularly personal statement.
It began as somebody else’s unfinished project, a disassembled truck, an accumulation of parts, and a vision that had never quite reached completion. Compton took that foundation and used it to pursue the kind of build he had wanted to execute on his own terms.
Three years later, the result combines a powder-coated factory chassis, big brakes, a static drop, 20-inch Detroit Steel wheels, LS power, overdrive cruising, custom upholstery, modern climate control, and award-winning paint without losing the unmistakable identity of a 1974 GMC square body.
More importantly, it gets driven.
Above: Photo courtesy of the owner
The long maiden voyage to SLO Down proved that. The Best of Show – Paint award in Anaheim validated the craftsmanship. And nearly 2,000 miles behind the wheel show that this GMC’s story isn't ending with the completion of the build.
For a truck that arrived in pieces and was literally assembled in a barn, that’s a pretty remarkable second life.
Vehicle: 1974 GMC C15 Super Custom Short Bed Fleetside
Owner/Builder: Chad Compton
Engine: 6.0L LQ4 LS
Transmission: 4L80 automatic
Rear Axle: Eaton TruTrac Posi-traction rear end installed July 2026
Wheels: Detroit Steel, 20x8 front / 20x11 rear
Tires: Diamond Back Classics, 235/40R20 front / 305/35R20 rear
Paint: Custom PPG Sky Blue / PPG 2185 White
Notable Award: Best of Show – Paint, I Am America, Anaheim Convention Center, 2025
Classic Industries Sells GM Truck Parts
Regardless of whether you're renewing a short bed fender-side GMC or Chevrolet pickup, it's a fleetside long bed, or any other sort of configuration, Classic Industries has a great supply of GM pickup components. GM truck owners can shop online for Chevrolet pickups here. Your online shopping for GMC is also too easy and fun.
GM truck owners can supplement the online shopping experience by ordering a free printed Chevrolet/GMC Truck Parts and Accessories Catalog by clicking on the button below.
