Ryan Wehrli’s Duramax-Equipped 1970 Chevrolet C-10

Ryan Wehrli has always been a truck guy who loves older iron, especially the 1967-72 C-10s. After a few years of driving his Cummins-powered ’06 Dodge, he grew bored with it, so he embarked on a new project to make an old truck new again. As the fabrication shop manager for Wehrli Custom Fab (WCFab) in Sycamore, Illinois, he had the expertise and access to the tools and space needed to create his dream truck. He hoped to find a C-10 truck, and then put a Duramax drivetrain and chassis underneath it to make it the ultimate driver.

When a WCFab customer wanted to sell his ’06 2WD regular cab long-bed truck, Wehrli knew he’d discovered the foundation for his project and scooped it up. It was a nice truck, and he was able to sell off most of the body parts for about half the purchase price, making the chassis and drivetrain a good bargain find for his project. The hunt for a solid C-10 continued for about four months before he found the ’70 C-10 you see here. Wehrli purchased it as soon as he saw it online and began to tear it down almost immediately with plans to have it on the road in just a few months. Instead, shop obligations took increasing precedence over his personal truck, and the project’s time line stretched to almost two years.

If you happen to see a rusty-green old C-10 at a show, you might want to take a closer look. It could be one of the coolest diesel trucks  you’ve ever seen.”

Wehrli started from the ground up, stripping the ’06 all the way down to bare frame. He cut everything off the frame except for the motor mounts and the two cross members. He wanted his new creation to be a 4WD rig, but rather than trying to swap a late-model IFS setup under the C-10, he wanted to go with a proven straight axle design to show off the WCFab crew’s capabilities. Since the C-10 has a shorter wheelbase than the Silverado, he knew he would have to relocate the axles anyway, so removing the mounts wasn’t an issue. After fitting the bed and cab to the chassis, he welded the new mounts, including provisions to install the Duramax core support to hold the radiator and intercooler. For better packaging and ride quality, Wehrli designed and fabricated a 4-link design with airbags front and rear.

To improve the chassis’ visuals, Wehrli welded up all of the holes in the frame and smoothed the entire chassis before sending it out to KB Customs (Sugar Grove, IL) to have it painted black with semi-gloss clear. Up front, he added a high-pinion Dana 60 axle fit with WFO Concepts crossover-style steering linkage and the factory 2006 steering box, along with WFO mount plates that allow the factory 2006 brake rotors and calipers to be used. To upgrade the stopping power, he replaced the factory rotors and pads with EBC Brakes slotted rotors and more aggressive pads. Since WCFab does powder-coating in-house, the crew coated the axle housing with gloss black and finished the links, pan-hard bar and steering components with dark metallic gray to complement the matte black frame. Seven-inch Slam Specialties airbags are used in conjunction with a pair of Bilstein 7100 series remote reservoir shocks up front to tame the ride and control the axle.

In the rear, Wehrli used the 11.5-inch AAM axle from the donor truck, but did away with the leaf springs in favor of a set of 6-inch Slam Specialties airbags and a 4-link design. The airbags are located directly between the frame and axle housing, while a set of Bilstein 7100 series remote reservoir shocks are mounted on the rear of the axle with a custom cross member for the upper mounts. He fabricated the link arms from 1.875-inch DOM steel tubing with a thick 3/16-inch wall and used large 2.625 Ballistic forged chrome-moly joints at each end of the links, as he did up front, for strength and good handling characteristics. The rear axle and suspension links were powder-coated to match the front as well. EBC rotors and pads improve the rear braking.

Wehrli fabricated cab mounts to place the cab on the new chassis where the engine would clear the firewall and allow the use of the Silverado core support and factory Duramax cooling fan. To mount the bed as low as possible on the chassis, Wehrli cut out the original ribs under the bed and replaced them with shorter versions to properly align the body and cab. The fabricated mounts look like a design that could have come straight from Chevrolet.

While Wehrli could have opted to have the C-10 body reworked and massaged to perfection and repainted a fresh, new color, he loved the patina of the original paint so much that he decided to leave it alone. He did go ahead and have a local body shop install new floor pans and rockers to replace the damaged originals. They also installed a larger transmission hump, like the ones in K-10 trucks, to clear the larger transmission and transfer case.

With the chassis and body whipped into submission, it was time to build the power plant. If Wehrli worked anywhere other than WCFab it might be acceptable to plug the stock Duramax into the truck and call it a day, but that just wouldn’t fly for the WCFab team. The crew tore into the LBZ to give it a mild performance rebuild. The block and parts were sent to Performance Motor Sports in Sandwich, Illinois, for machine work, and then brought back to WCFab for assembly. The crew put together a mix of factory and aftermarket parts to make Wehrli’s goal of streetable and reliable 750 hp a reality.

At the heart of the Duramax engine rests a new factory LML crankshaft that swings around delipped LB7 pistons on stock LBZ rods with an ATI damper to keep harmonics in check. A SoCal Diesel Performance alternate-fire camshaft actuates the valves through Merchant Automotive pushrods with Hamilton Cams valve springs. Internally, the engine is held together with ARP head and main studs, and new bearings were used throughout the engine. Everything else was replaced or rebuilt during reassembly, including the alternator, starter, water pump, oil cooler, oil pump and power steering pump. To help the engine look its best, all of the brackets and covers were powder-coated in-house, and all new fasteners were used throughout.

Spent exhaust gases are expelled through a set of LML manifolds then channeled through a set of 2-inch-diameter stainless steel up-pipes. Wehrli fabricated the pipes to carry the hot exhaust gasses up to a fabricated turbo pedestal in the valley that rotates the turbo 90 degrees. The valley charger is a High Tech Turbo FMW S366 that sends the exhaust along to a High Tech Turbo FMW S480 atmosphere turbo mounted on the passenger side of the engine. From there, the exhaust is routed through a polished stainless steel 5-inch-diameter exhaust system that terminates behind the passenger side rear wheel. All of the under-hood hot side piping is covered in header wrap to keep the heat in the pipes and out of the engine bay.

For the intake, plenty of clean air is drawn into the HTT S480 turbo through an aFe Pro DryS cone filter. After the air is compressed, it’s handed off to the HTT S366 in the valley before being channeled through the factory GM intercooler and routed into the engine through a WCFab Y-bridge intake. Wehrli used Vibrant VanJen clamps and welded V-band clamps to plumb the compound turbo setup to minimize the chance of exhaust or boost leaks and make it easy to service while providing an ultra-clean look. All of the cold side pipes and the turbo compressor housings were powder-coated black, and then given a gold flake clearcoat for a unique look under the hood that’s sure to draw attention to the excellent fabrication work and unique compound turbo setup.

Wehrli simplified and cleaned up the engine harness, protecting it with a braided sheath for a much cleaner look than the factory provides. A single stroker 10mm Exergy CP3 is installed in the AC compressor location; a WCFab machined billet pulley spins it, while a WCFab block-off plate has been installed in the stock CP3 location in the valley. The high-pressure fuel is fed into the engine through a set of 60% over Exergy fuel injectors. EFILive tuning by Calibrated Power Solutions is used to get the most out of the combination, yielding 753 hp and 1,390 lb-ft of torque as measured on CPS’ dyno and meeting Wehrli’s power goal for the truck.

All of that modern Duramax power would easily overwhelm the original transmission, so Wehrli opted to go the modern route and use the Allison from the ’06 Silverado. The transmission was reconfigured with a 4WD output and connected to a factory transfer case that was powder-coated black to match the rest of the chassis. The transmission was given a performance rebuild by the WCFab team with SunCoast internals to handle the extra power. The engine is linked to the transmission through an LML flex plate and SunCoast 1058 triple disc billet torque converter, while custom drive shafts send the power to the front and rear axles.

To make the truck more comfortable, Wehrli installed sound-deadening material on the firewall and cab floor, and then installed a new carpet kit and the seats from the Silverado. The Silverado’s steering column and wheel were also adapted to the C-10 interior, as was the gauge cluster. The rest of the interior is stock C-10 down to the simple door panels, crank windows, classic sun visors and steel dash. Wehrli hopes to one day install a stereo system in the truck, but right now he’s having too much fun enjoying the sound of 750 Duramax horses snarling each time he mashes the loud pedal.

Like most truck guys, Wehrli says his truck still isn’t done. He would like to install heat and AC to make the truck more enjoyable to drive, as well as some additional custom touches, but he is certainly enjoying the C-10 as it is now. He finished it in time to debut it at the 2016 Scheid Diesel Extravaganza, where it took home the Best Custom Diesel honors for Saturday’s show ’n’ shine. It’s not a trailer queen either, as Wehrli has put more than 4,000 miles on the truck in the five months since he finished it, attending diesel events and just plain having fun in his dream ride. If you happen to see a rusty-green old C-10 at a show, you might want to take a closer look. It could be one of the coolest diesel trucks you’ve ever seen.

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BUILD SPECS

OWNER

Ryan Wehrli
1970 Chevy C-10
Sycamore, Illinois

Engine

• LBZ Duramax diesel engine with compound turbo setup and machine work by Performance Motor Sports in Sandwich, IL
• 753-hp and 1,390-tq
• ARP head and main studs
• LML crankshaft
• SoCal Diesel Performance alternate-fire camshaft
• Merchant Automotive pushrods
• Hamilton Cams valve springs
• ATI harmonic damper
• LML exhaust manifolds
• Custom 5-inch exhaust
• High Tech Turbo FMW S366 and S480 turbos
• aFe Pro DryS cone filter
• WCFab Y-Bridge intake
• 2006 Chevy intercooler
• Exergy 10mm CP3
• Exergy fuel injectors
• Calibrated Power Solutions EFILive tuning
• 2006 Chevy radiator and fan
• LML flex plate
• SunCoast 1058 triple disc billet torque converter
• Allison transmission
• 2006 Chevy transfer case
• 2006 Chevy fuel tank
• FuelLab pump and filter system

Chassis & Suspension

• 2006 Chevy Silverado frame with custom body mounts
• Powder-coating by KB Customs of Sugar Grove, IL
• Custom front and rear 4-link with pan hard bar
• Slam Specialties airbags
• Bilstein 7100 series remote reservoir shocks
• Dana 60 front axle
• AAM 11.5-inch rear axle
• WFO Concepts crossover steering with 2006 Chevy steering box
• EBC slotted rotors and brake pads

Wheels & Tires

• 20×10-inch Drop Stars 645MB wheels
• 35×12.50R20LT General Grabber AT2 tires

Body & Paint

• Original patina
• Replacement floor pans
• 4×4 transmission hump
• Replacement chrome front bumper
• Custom-fabricated rear bumper

Interior & Stereo

• Sound deadening material
• Replacement carpet
• 2006 Chevy bucket seats, steering column, steering wheel and gauge cluster

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