One Hot 900 Horsepower Duramax

Daily Driver-Turned 900HP Work Stock Puller

Just as in any other industry, being in-the-know in your specific corner of the automotive world can land you exceptional deals from time to time. When Jeff McCord, owner of LinCo Diesel Performance in Troy, Missouri, heard there was an LB7 with a “blue” engine in it for sale at the local dealership, he pounced. As it turns out, the ’02 Silverado 2500 HD had a fully-built SoCal Diesel mill under the hood, and the truck had only been traded in because the previous owner couldn’t get a transmission to live behind it. Well, as it turns out, Jeff’s company specializes in beefing up Allison 1000s. So not only did he score a clean, four-wheel drive ¾-ton Chevy with a built LB7 for a cool $8,000, but he had it up and running the very next day.

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Under the hood of Jeff McCord’s ’02 Chevy Silverado 2500 HD and beneath all the polished aluminum piping, turbo, and Wagler intake, sits a balanced and blueprinted LB7 Duramax from SoCal Diesel. Installed by the truck’s previous owner and with few expenses spared, it sports a girdle, ARP main studs, Carrillo rods, 0.020-inch overbore Mahle cast-aluminum pistons with 0.120-inch valve reliefs, a SoCal #9100 standard firing order camshaft, and an O-ringed block. SoCal’s Stage 2 heads, complete with 5-axis CNC porting, beehive valve springs with titanium retainers, and billet single-piece rocker bridges, anchor to the block via 14mm ARP head studs.

Daily Driver-Turned Sled Puller

Following six months of using the truck as his daily driver, Jeff decided to transform the ’02 into a competitive puller. With a goal of pulling in Work Stock, a popular and highly competitive class in his neck of the woods, Jeff knew he had his work cut out for him. For starters, at least 800 rwhp would be required to run at the front, countless IFS, chassis, and axle changes would need to be made, and an off-the-shelf turbocharger simply wouldn’t cut it. Surrounded by employees eager to see the truck storm past the 300-foot mark, Jeff and his team tore into the classic body Bow Tie. The following is what they came up with.

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Arguably the best combination of DOT tires in the truck pulling world, Jeff’s Silverado makes use of 35-inch Nitto Mud Grapplers up front and BFGoodrich All-Terrain T/As in the rear. The Mud Grapplers are typically aired down to 18 to 22 psi for a wide bite, while the BFGs are kept between 50 to 55 psi for minimum give and maximum trenching effect. All four tires mount to American Racing Baja wheels, though the fronts are 16x10s and the rears measure 16×8.

SoCal-Built LB7

After tracking down the original owner and getting the full scoop on the SoCal engine, Jeff had all the reassurance he needed to start adding horsepower. That reassurance consists of the factory crankshaft being secured by way of a main cap girdle and ARP main studs, Carrillo rods and fly-cut cast-aluminum Mahle pistons, SoCal’s 9100 model camshaft, and the block being machined to accept 14 mm head studs and O-rings. Stage 2 ported heads with larger stainless steel intake valves and upsized Inconel exhaust valves flow an additional 75 cfm per cylinder.

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Don’t let the polished compressor housing fool you: this little S300 means business. Even though it’s way overfueled, the 66 mm charger moves enough air to support nearly 900 rwhp. Custom-built by Stainless Diesel, it features the company’s signature 5-blade, billet compressor wheel, a 74 mm turbine wheel (exducer), and a non-wastegated T4 divided exhaust housing with a 1.10 A/R. The S366 mounts to a twisted pedestal from Wagler Competition Products and works in conjunction with Wagler’s one-piece cast street intake manifold.

An Air-Limited 900HP

With regional Work Stock class rules limiting turbo size to a T4 flanged S300 with a 66 mm inducer compressor, Jeff turned to the pros at Stainless Diesel to get the most out of a small-frame BorgWarner charger. Each time out, the custom-built 5-blade S366 builds 55 psi of boost and survives more than 70 psi of drive pressure while supporting nearly 900 hp. A Wagler Competition Products twisted pedestal locates the turbo at the rear of the valley, just behind a Wagler street intake manifold, and all piping to and from the Mishimoto intercooler were fabbed up at LinCo Diesel Performance courtesy of Tyler Turay.

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Overkill Fuel System

Thanks to dual injection pumps being permitted in Work Stock, Jeff makes the most of it. A belt-driven PowerFlo 750 CP3 from Fleece resides up top, a 12 mm stroker pump from Exergy Performance sits in the factory location, and a PPE CP3 controller ties them both together. On the low pressure side, each CP3 benefits from its own dedicated 250-gph FASS system. On the high-pressure side, a set of Exergy 250-percent over injectors distribute as much as 26,500 psi in-cylinder.

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To maintain rail pressure with a 250-percent over injector sitting above each cylinder, the PPE Dual Fueler system already aboard the truck was upgraded with larger displacement CP3s. Up top, a belt-driven 10 mm PowerFlo 750 pump from Fleece Performance Engineering got the call, while a 12 mm CP3 from Exergy Performance was installed in the factory location. Also notice the HSP Diesel billet thermostat housing, which allows the driver side coolant hose to clear the top CP3.

Full-Billet Allison, Danville Tuning

Fully prepped for active pulling duty, the LinCo-built Allison sports all billet shafts, an Xcaliber 6-pinion billet P2 planetary and billet C2 hub, Sun Coast GMax clutch kit, and was topped off with a Sun Coast 3,200-rpm stall triple-disc converter. To lock the converter at the exact moment he needs to, Jeff relies on a Dirty Alli-Locker lockup switch from DHD. Thanks to the built Allison and SoCal engine, Danville Performance is able to get the absolute most out of the overkill injection system and 5-blade turbocharger via EFI Live tuning.

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Just as each CP3 has its own dedicated fuel system supplying it diesel, a G&R Diesel dual-feed sump provides each FASS system its own supply line from the factory tank. The billet-aluminum piece also features an integrated return, complete with two ½-inch return ports.

Double-edged Sword

Still working with a relatively fresh build, Jeff plans to spend the summer pitting his Duramax against some of the stiffest Work Stock competition in the Midwest. But that’s not all. He is strongly considering the possibility of swapping a 2.6-inch smooth bore charger in place of the S366, dropping 500 pounds, and joining the 8,000-pound Pro Street Diesel Truck class on occasion—and possibly even running both categories at the same event. If that happens, you’ll likely see this four-door Bow Tie digging its way to the front of not one, but two of the toughest classes in truck pulling.

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With the street series traction bars quelling axle wrap, the rear AAM 1150 was further reinforced with a rear truss from Artec Industries. Recently, Jeff switched to a staggered ring and pinion arrangement consisting of 4.56:1 up front and 4.88s out back. Inside the rear differential you’ll also find a spool. The heavy-duty, reworked Reese-style hitch with added cross members was fabricated by friend and employee Tyler Turay.

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Tucked away on the inside of the driver side frame rail, two Titanium Signature Series fuel systems from FASS are present. Each 250-gph system feeds one CP3 a consistent 10 psi through ½-inch fuel hose. To get an idea of just how much overkill these pumps provide, one system on its own can support up to 1,200 hp.

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With a goal of having some upward travel but zero downward travel, preload bolts help control the front end’s minimum height by essentially taking the torsion bars out of the equation. Now all the weight up front is bearing down on the control arms, and ultimately the tires.

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As a show of how tough his company’s in-house traction bars are, Jeff grabbed a set of his street series traction bars from off the shelf and bolted them onto the puller. The bars are built from 1.75-inch DOM tubing, utilize bolt-on axle mounts, bolt-on frame mounts that accommodate larger U-bolts, and incorporate beefy, 7/8-inch heim joints.

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There might not be a fancy aftermarket pan on this Allison, but internally it’s about as serious as it gets. Built in-house at LinCo Diesel Performance, the five-speed auto received billet input, intermediate, and output shafts, the Xcaliber 6-pinion billet P2 planetary and billet C2 hub, a Sun Coast GMax clutch kit, and a performance valve body with a TransGo Jr. shift kit and modified separator plate. A Sun Coast 1072 model triple-disc converter with a billet stator and a 3,200-rpm stall is tasked with transferring power, and it does its job very well.

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In order to make sure the factory-based IFS works as effectively as possible, Jeff and his team took steps to both strengthen and optimize its operation during the course of a pull. By utilizing a pair of nitrogen-charged (and inverted) 2.5-inch body, 2.5-inch stroke bump stops from Locked Off-Road, chassis lift is controlled. Under load while hooked to the sled, the chassis is only allowed to rise enough for the CV shafts to work in a straight line—when they’re at their strongest. Steering is reinforced thanks to a set of PPE Stage 2 tie rods and a straight center link.

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As with any pulling truck equipped with an automatic transmission, locking (and unlocking) the converter at the precise interval can mean the difference between winning and losing. To give him the best chance of inching out the competition, Jeff relies on a Dirty Alli-Locker from Dirty Hooker Diesel. Once engine speed reaches 3,500 and he’s sure he can carry his 3,700 rpm target speed down the track, Jeff locks the converter. A typical pull entails the transfer case being in low range, fourth gear being selected in the Allison, and the converter getting locked somewhere between the 50- and 100-foot mark, depending on the track.