Hard Work Pays Off - Diesel World

A Cummins-Swapped ’08 Super Duty Packing A 4R100 And 700 HP

An ’08 Super Duty was a truck that John Schomberg always wanted. Unfortunately, the 6.4L Power Stroke under the hood of his King Ranch F-350 suffered a bottom-end failure within the first 6,000 miles of ownership…and with only 103,000 on the odometer. Following the local Ford dealership’s quote of $17,000 to replace the engine, naturally John began to weigh other options. After reaching out to Jeff McCord at LinCo Diesel Performance, the two parties had a game plan—and it involved converting the Ford to Cummins power. “LinCo wasn’t the cheapest, but they took the time to walk me through everything involved in the Cummins swap,” John told us. “And honestly, they were one of the only shops that wanted to do it.”

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John Schomberg’s Cummins swap revolves around the use of a 2006 model year common-rail. While in the care of LDP Machine in Troy, Missouri, the 5.9L was transformed into one of the company’s Stage 2 engines, a build that’s guaranteed for 750 hp. ARP main studs and rod bolts, thermal coated Clevite H-series main bearings, Attitude Performance billet-aluminum saddle jet plugs, stock compression, 0.040-inch overbore ’04.5-’07 cast-aluminum Mahle pistons, and a Stage 3 “Big Stick” camshaft (and tappets) from Colt Cams all made the cut. Behind the fan shroud, a mechanical fan clutch from a 7.3L (and made possible courtesy of a GOS Racing fan clutch adapter hub) is employed.

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A resurfaced head anchors to the block through the use of ARP head studs, and for a bit of bling, a billet valve cover from G&R Diesel was added. Valvetrain upgrades include the addition of XDP street performance 3/8-inch diameter chromoly pushrods and Hamilton Cams’ 103-lb valve springs, while a LinCo Diesel Performance billet grid heater delete provides a restriction-free path for air entering the head.

Unbeknownst to many, a Cummins conversion isn’t typically the most affordable path for Ford owners. Sure, the end result is a simpler engine with what the owner hopes will be a less problematic means of propulsion, but performing a Cummins swap is anything but easy—or budget-friendly. And sometimes, there isn’t even a guarantee the Cummins you install will last. Case in point, the original ’06 take-out engine John went with lost a factory piston cooling nozzle while drag racing, the result of which was a melted piston in cylinder number 4.

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Tucked away in the factory location is a Killer B turbo from BD Diesel. The S300 BorgWarner-based charger conceals a 63mm compressor wheel, and a 65mm turbine wheel inside a 14cm2 exhaust housing. The internally wastegated turbo bolts to a two-piece BD exhaust manifold and easily tops 40 psi of boost when it’s leaned on. The 6.4L intercooler, along with the 6.4L radiator and degas bottle for that matter, was retained.

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Throwing plenty of fuel at the 63mm turbo, a set of 80-percent over injectors from S&S Diesel Motorsport are supported by one of the company’s proven 10mm CP3’s. The 6.7L Cummins-based stroker pump boasts a 22-percent displacement increase over stock and—combined with the injectors—can easily support 700-rwhp.

A Long-Block Fit To Handle 750 HP

To ensure the 5.9L common-rail never suffered another mechanical fluke, John pulled out all the stops and had LDP Machine treat the Cummins to one of its Stage 2 builds. Bottom end upgrades included ARP main studs and coated Clevite H-series main bearings, ARP rod bolts and Clevite A-series rod bearings, 0.040-inch over stock replacement ’04.5-’07 Mahle pistons, a Stage 3 cam from Colt, and Attitude Performance’s billet-aluminum saddle jet plugs. Up top, the resurfaced cylinder head was graced with Hamilton Cams’ 103-lb valve springs and fastened to the block via ARP head studs.

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In order to optimize the potential of the upgraded common-rail system, a 165-gph Titanium series lift pump from FASS sits outside the driver side frame rail. The system pulls fuel from a FASS sump installed in the factory tank and keeps a steady 18-psi worth of supply pressure on tap for the 10mm CP3 at all times.

Enough Fuel For 800 HP

With the engine’s threshold for pain now sitting at 750-hp, there was no better time to round up the fuel system parts that could push the long-block’s advertised power rating. For a solid, all-around setup that could burn cleanly, easily make north of 650-rwhp, and still allow John to tow anything he needed to, a 10mm CP3 and 80-percent over injectors were sourced from S&S Diesel Motorsport. Low-pressure fuel supply comes by way of a 165-gph Titanium series FASS system that pulls fuel from a sump in the factory Ford tank.

Quick-Lighting Turbo

Because John still tows with the truck on a regular basis, he needed a turbo that would spool quickly yet also support the 650 to 700-hp he was after. To fit the bill, the old-school Killer B from BD Diesel got the call. The S300-based charger sports a 63mm compressor wheel, bolts to one of BD’s two-piece, third-gen T3 exhaust manifolds, and builds more than 40 psi of boost under load. The 63mm compressor also keeps John legal in the Work Stock class in case he ever decides to hook the truck to the sled…

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With just 123,000 miles on the truck, the King Ranch interior has a lot of life left to give and appears all but brand-new. Analog gauges along the A-pillar allow John to keep tabs on transmission temperature, boost pressure, and exhaust gas temperature.

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After attempting to run several 5R110 TorqShift automatics behind the Cummins, John turned to the guys at LinCo for a 4R100 swap. The four-speed auto is controlled via a PCS TCM2000 controller, with the manual lockup switch shown here (and positioned in the dash) wired directly into it. A DeStroked adapter plate and billet flex plate made integrating the 4R100 possible, while LinCo treated its internals to a Category 5 kit from Sun Coast. The torque converter, a custom conversion triple disc from Sun Coast, features a low, 1,800 to 2,000-rpm stall speed.

Trials, Tribulations, and Transmissions

Despite John’s willingness to swap a Cummins in place under the hood, he did anything but spring for a 48RE to put behind it. Instead, he decided to give the factory 5R110 TorqShift a go—a decision both he and the TorqShift came to regret. Then when a second stock 5R110 couldn’t hack it behind the grunt of the Cummins, John gave a built version a try. Unfortunately, even after stepping up to what he thought would be a solid combination, the five-speed auto and the Cummins never could quite get along. But rather than give in and go with a built 48RE, he opted for another four-speed automatic: Ford’s 4R100. Assembled at LinCo Diesel Performance using Sun Coast internals and controlled by a TCM 2000 from Powertrain Control Solutions, the 4R100 has yet to skip a beat.

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Trust us, seeing a CSP5 switch in the cab of a Ford takes some getting used to. However, the spot-on EFI Live tuning from Maverick Diesel does not. Thanks to Maverick’s keyboard wizardry the truck is responsive, stays cool, and runs extremely clean given the extent of the fuel system mods.

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Although the F-350 was originally equipped with an electronically shifted NV273 transfer case, it was switched over to a manually shifted NV271F during the 4R100 swap. Inland Truck Parts Company in nearby St. Charles, Missouri, built the driveshafts to make the 4R100/NV271 combination work, which meant a shorter driveshaft in the rear and a longer one up front.

The Payoff

Make no mistake, John’s “Fummins” project was no walk in the park. From hunting down a shop that actually wanted to tackle the swap, to the original 5.9L losing a piston cooling nozzle and melting a piston, to all of the truck’s transmission issues, it was anything but an easy road to get here. Luckily, John is no stranger to hard work and never gave up on his goal of owning the perfect truck. Now, with the powertrain in his F-350 rock-solid reliable, comes the payoff: 700-hp, the ability to tow anything you want, and smiles. Lots of smiles.

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To keep the factory Ford 10.5 axle from wrapping and the Super Duty’s rear leaf springs from twisting under 1,400 lb-ft of torque, John installed a set of LinCo Diesel Performance’s street series traction bars. The universal traction bars feature bolt-on brackets and were treated to trusses for added strength, along with Pewter powder coating that matches the truck’s two-tone paint scheme.

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As a union carpenter, John appropriately has Labor Omnia Vincit stenciled across the truck’s brow on the windshield. It means “work conquers all” and is a phrase his late father, also a union carpenter, lived by. John does the same.

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