Ryan Wehrli’s 1970 Chevrolet C/10 Duramax
Ryan Wehrli has always been a truck guy with a great love of older iron, especially the 1967-72 C/10 Chevrolets. After a few years of driving his Cummins-powered 2006 Dodge and getting bored with it, he decided to start a new project: making an old truck new again. As the fabrication shop manager for Wehrli Custom Fab 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 then put a Duramax drivetrain and chassis underneath it to make it the ultimate driver.
When a WCFAB customer wanted to sell his 2006 2WD regular cab long bed truck, Wehrli knew he had found 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 good C/10 went on for about four months before he found the 1970 C/10 you see here, which came from North Carolina to Illinois via its previous owner, who intended to build it
RYAN WEHRLI’S 1970 CHEVROLET C/10 DURAMAX
but ended up listing it online after owning it for about a year. Wehrli purchased it as soon as he saw it and began to tear down the pair of trucks almost immediately with plans on having it on the road in just a few months. But as the project escalated and shop obligations were put ahead of the project truck the time line inflated and it took nearly two years to complete.
Wehrli started from the ground up by stripping the 2006 all the way down to the bare frame; he cut everything off the frame except for the motor mounts and 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 fabrication capabilities they have at the shop. And since the C/10 has a shorter wheelbase than the Silverado, he knew he would have to relocate the axles anyhow so removing the mounts was not an issue. After fitting the bed and cab to the chassis he welded on 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 four-link design with air bags front and rear.
To improve the visuals of the chassis, Wehrli welded all of the holes in the frame closed and smoothed the entire chassis before sending it out to KB Customs in nearby Sugar Grove to get it painted black with a semi-gloss clear to make it look good and hold up well to the elements. Up front he’s using a high-pinion Dana 60 axle that he 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 Orangestuff pads. Since WCFAB does powdercoating in-house, they coated the axle housing gloss black and finished the links, Panhard bar and steering components with a dark metallic gray to stand out from and compliment the matteblack frame. Seven-inch Slam Specialties air bags 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 air bags and a four-link design. The air bags are located directly between the frame and axle housing while a set of Bilstein 7100-series remote reservoir shocks are mounted on the rear side 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 chromoly 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 powdercoated to match the front as well. EBC slotted rotors and Orangestuff pads are employed to improve the rear braking as well.
Wehrli fabricated cab mounts to place the cab on the new chassis where the engine would clear the firewall while also allowing the Silverado core support to be retained and the factory Duramax cooling fan to be used. 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 ribs to properly align the body and cab. The fabricated mounts look as though Chevrolet planned to mate the Silverado chassis to a C/10 body to begin with.
While Wehrli could have opted to have the C/10 body reworked and massaged to perfection then paint it a fresh new color, he loved the patina of the original paint so much that he decided to keep it the way it was when he bought it. He did go ahead and have a local body shop install new floor pans and rockers to replace the damaged original panels. They also installed a larger transmission tunnel like the ones fitted in the 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 Wehrli Custom Fabrication 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, so they tore into the LBZ to give it a mild performance rebuild. The block and parts were sent off to Performance Motor Sports in Sandwich, IL, for machine work then brought back to WCFAB for assembly. The WCFAB crew put together a mix of factory and aftermarket parts to try to make Wehrli’s goal of 750 streetable and reliable horsepower.
At the heart of the Duramax engine a new
At the heart of the Duramax engine 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 to control the valves. 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 the reassembly including the alternator, starter, water pump, oil cooler, oil pump, and power steering pump. To help the engine to look its best, all of the brackets and covers were powdercoated 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 that Wehrli fabricated 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 sent out through mostly stock routing 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 wrapped in header wrap to keep the heat in the pipes and out of the engine bay.
On the intake side, plenty of clean air is drawn into the HTT S480 turbo through an afe Pro Drys cone filter then after it is compressed it is handed off to the HTT S366 in the valley before being channeled through the factory GM intercooler then 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 giving an ultra-clean look. All of the cold-side pipes and the turbo compressor housings were powdercoated black then given a gold flake clear coat 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 braided sheath for a much cleaner look than the factory provides. A single stroker 10mm Exergy CP3 is installed in the AC compressor location; it is spun by a WCFAB machined billet pulley while a WCFAB block off plate
is 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 horsepower 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 transmission originally in the C/10, 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 powdercoated 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 a LML flexplate 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 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 is 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 is 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 diesel show, you may want to take a closer look. It may be one of the nicest diesel trucks you’ve ever seen—we know it’s one of the nicest custom trucks we’ve seen! UDBG