Top Notch Garage’s Compound-Turbo 3.0L Duramax Silverado

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Top Notch Garage Built the Regular Cab, Short-Bed Duramax Silverado Chevrolet Wouldn’t

Somebody at GM needs to explain why this truck doesn’t exist.

Not this exact truck, obviously. Forty-inch Mickey Thompsons, compound turbos, and long-travel suspension might be asking a little too much from the factory warranty department. But a regular cab, short-bed, four-wheel-drive Silverado with the 3.0L Duramax? Come on.

Top Notch Garage got tired of waiting. The Texas diesel shop wanted a half-ton shop truck that was compact, diesel-powered, and genuinely different. Chevrolet wasn’t going to build it for them, so Josh Harris, Josh Chambers, Micah Howard, and the Top Notch crew decided to do something better. They built their own. And wherever possible, they used GM’s parts to do it.

RAID THE PARTS BIN
This project didn’t start with a complete truck. Top Notch bought a wrecked 2022 Silverado LT double cab equipped with the 3.0L Duramax and four-wheel drive, then stripped out essentially everything they needed: the engine, 10L80 transmission, transfer case, wiring, modules, and interior.

Next came a brand-new GM regular cab, short-bed frame, and a salvage yard half-ton regular cab. Then they added another factory donor to the equation. A 2024 Silverado 1500 ZR2 supplied the front and rear axles, complete with factory electronic locking differentials and 3.23 gears.

At that point, this wasn’t a cheap trim conversion. It was Top Notch assembling the ultimate short-bed Silverado that Chevrolet could have built using pieces Chevrolet already makes. Then the team stopped pretending they were going to keep it factory.

MAKE ROOM FOR 40s
An LSK long-arm, long-travel suspension system sits underneath the truck, paired with Eibach front springs, Deaver rear leaf packs, and adjustable King shocks.

Top Notch then chose massive 40×13.50R17 Mickey Thompson Baja Boss M/T tires mounted on a set of 17×9 Thret 602 Maze beadlock wheels. There was just one slight problem. The long-travel suspension and FiberwerX bodywork were originally engineered to clear a 37-inch tire. Top Notch wanted 40s. So, the truck was going to fit 40s.

The firewall was tubbed, the fender aprons were shaved, and the body was extensively clearanced so those massive tires could travel through the suspension cycle without turning expensive sheetmetal into its own self-clearancing system. FiberwerX front fenders and bedsides accommodate the LSK’s wider track, while Addictive Desert Designs ZR2 Stealth Fighter front and rear bumpers protect both ends. Even the front bumper required extensive fabrication and reshaping to follow the widebody lines and to clear the tires. That’s the difference between bolting on 40s and actually building a truck for them.

TWO TURBOS, LITTLE DURAMAX
Now we get to the fun part. GM’s 3.0L inline-six Duramax is a great little diesel, but Top Notch decided one turbo wasn’t enough. The crew at JStar Fabrications out of Bristolville, Ohio, built a custom compound turbo system, retaining the factory variable-geometry charger and compounding it with a massive Forced Inductions ball-bearing unit.

That introduced a structural problem. Boost could now push well beyond 50 psi, and the factory Duramax intake manifold is molded plastic. Nobody involved felt particularly interested in discovering its exact breaking point. G&R Diesel solved the problem by supplying a gorgeous custom billet intake manifold, completely eliminating that weak plastic link before it could burst.

PPE Diesel also supplied an upgraded water-to-air intercooler and heat exchanger, along with an upgraded aluminum oil pan, a high-capacity transmission pan, and a cooler bypass valve delete. With the compounds, airflow, cooling, and tuning working together, Top Notch says the little 3.0L can effortlessly spin the 40-inch tires. That’s a sentence Chevrolet definitely didn’t put in the truck’s factory brochure.

SHOW TRUCK. REAL TRUCK
This build could’ve gotten away with just being outrageous under the hood. Instead, Top Notch obsessed over the cosmetic finish. Jeremy Donald at Chambers Paint and Body sprayed the truck in a striking BMW San Marino Blue two-stage metallic paint. The deep blue color absolutely explodes against the clean black hardware and custom powdercoated chassis pieces.

Baja Designs lighting went on, described in Top Notch’s own wonderfully precise words as “all of ‘em everywhere.” High-intensity lights fill the bumpers, A-pillars, and roof, with additional lighting covering the bed and the underbody.

Inside, Katzkin black-and-gray leather and suede upholstery finished by Faries Top & Trim of Tyler, Texas, gives the one-off regular cab an interior worthy of the exterior. A Wilwood Aero6 Direct-Mount brake kit up front helps bring the whole heavy-duty package back down from speed.

Top Notch wanted something capable of doing exactly what it looked capable of doing but finished well enough to compete at a major show. The industry took notice. At Lone Star Throwdown, the regular cab landed straight in the coveted Top 100 out of thousands of custom builds. Mission accomplished.

THE TRUCK GM WOULDN’T BUILD
When asked what Top Notch would change about the truck after finishing it. Their answer? “Drive it more.”

We also asked about any shortcuts discovered during the two-month build. “Sleep under the truck.”

Main problem encountered? “Time.”

Solution? “Worked many long hours.”

You get the feeling these guys aren’t particularly interested in overcomplicating things. Except, family and shop reputation considered, their trucks tell a different story. This Silverado is wonderfully and beautifully complicated.

It took a wrecked double cab, a brand-new frame, a salvage yard cab, high-end ZR2 locking axles, custom bodywork, long-travel desert suspension, 40-inch mud terrains, compound turbos, a billet intake manifold, and many long hours to create something that sounds incredibly simple when you strip it all away—a cool, regular cab, diesel truck.

GM wouldn’t build it. Top Notch Garage did. And frankly, we like theirs better.

SPECIAL THANKS
Truck Guru, Thret Off-Road, Mickey Thompson, LSK Suspension, FiberwerX, Addictive Desert Designs, Baja Designs, PPE Diesel, Edge Products, Wilwood, Katzkin, Kicker, Prismatic Powders, JStar Fabrications, G&R Diesel

UPGRADES

2022 Chevrolet Silverado 1500

Owner: Top Notch Garage Van, Texas

ENGINE & DRIVETRAIN: 3.0L Duramax inline-six diesel; Custom compound-turbo setup; Forced Inductions FIS GTR 366 ball-bearing turbo; Turbo Fabrication by JStar Fabrications; G&R Diesel custom billet intake manifold; PPE Diesel upgraded water-to-air intercooler; PPE Diesel heat exchanger; 4-inch exhaust dump; Custom tuning; GM 10L80 10-speed automatic transmission; PPE Diesel high-capacity pan, upgraded cooling, and cooler-bypass delete; 2024 Silverado 1500 ZR2 front and rear axles with electronic locker; 3.23:1 gears; Wilwood Aero6 Direct-Mount front brakes

CHASSIS & SUSPENSION: GM regular cab/short-bed frame, modified and powdercoated; LSK long-arm, long-travel; Eibach front springs; Deaver leaf springs; King adjustable shocks

WHEELS & TIRES: 17×9 Thret Offroad 602 Maze beadlock wheels; 40×13.50R17 Mickey Thompson Baja Boss M/T tires

BODY & PAINT: BMW San Marino Blue paint by Jeremy Donald / Chambers Paint and Body; FiberwerX widebody front fenders; FiberwerX widebody bedsides; Addictive Desert Designs ZR2 Stealth Fighter custom-modified front bumper; Addictive Desert Designs ZR2 Stealth Fighter rear bumper; GM ZR2 grille and headlights; Tubbed firewall, shaved fender aprons, and additional clearance for 40-inch tires; Prismatic Powders finishes; Baja Designs lighting

INTERIOR: Katzkin black-and-gray leather and suede; Upholstery by Faries Top & Trim; Kicker audio

BUILD TEAM: Josh Harris, Josh Chambers, and Micah Howard

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Corey Decker

Corey Decker is a photographer and storyteller who views the world through a lens of authenticity. With a passion for capturing the raw beauty of landscapes and the quiet moments in between, Corey’s ...