A 1,200HP, 2,200 LB-FT ’08 SUPER DUTY
When you’re a horsepower junkie but don’t want to sacrifice the reliability of your $70,000 daily driver, what do you do? You buy a second truck and throw all restraint out the window. This is the path to four-digit power Chad Flynn took with his ’08 F-250, a former plow truck from Cleveland. In the diesel game since the early 2000s, Chad knows as well as anyone that there is a point of no return when modifying your primary means of transportation. Even worse, the quest for more and more power can turn sour if you’re constantly turning wrenches on the vehicle you rely on day-in and day-out. So rather than continue to push the limits of his brand-new 6.7L Power Stroke, he set his sights on making this regular cab 6.4L a 10-second play toy.


With a little over 62,000 original miles on the clock, Chad plucked the 6.4L Power Stroke out of the truck and set to work prepping it to handle big power. Good machine work and proven hard parts served as the foundation for the build. An externally balanced crankshaft, R&R connecting rods with ARP rod bolts, and standard bore, cut-and-coated MaxxForce 7 International pistons from RCD Performance made the list, along with Elite Diesel Engineering’s Stage 1X cam. The factory heads were resurfaced, outfitted with Elite’s Stage 2 valve springs and cryogenically-treated rocker arms, and clamped to the block via A1 Technologies H-11 head studs.


Well aware of the 6.4L Power Stroke’s highly potent common- rail injection system, Chad added a second K16 pump, 150-percent over injectors, and an A1000 lift pump—complete with garden hose-sized fuel lines—to back it all up. The twin K16 system came from Elite Diesel Engineering and uses an additional, belt-driven high-pressure fuel pump to keep the rails full of fuel. The 150-percent nozzles were sourced from RCD Performance and Chad started fresh by installing them on a brand-new set of OEM injectors. To keep the common-rail system happy, Chad pieced together his own low-pressure fuel system based around the use of the aforementioned (and competition-friendly) Aeromotive A1000.


The truck’s lightning quick spool up and big top-end power is directly linked to Elite Diesel Engineering’s Raw Power compound turbo arrangement. A 63mm factory-based VGT gets things started in a hurry, and an 88mm atmosphere charger from Precision Turbo and Engine comes on line at higher rpm. Dual wastegates allow the small-ish VGT to route excess drive pressure into the Precision unit to drive it harder. In instances where the 88mm charger sees too much drive, the second gate opens, venting exhaust into the downpipe.


Surviving the more than 2,200 lb-ft of grunt the truck produces— not to mention the shifts that are made with that much twist on tap—is a Stage 5 TorqShift from Elite Diesel Engineering. The fortified five-speed features an Aermet input shaft, 300M intermediate shaft, a billet overdrive planetary and Low/Reverse hub, and is packed full of GPZ clutches from Raybestos. A 13-inch, four-disc converter from Diesel Performance Converters handles torque transfer and a drop-in Mishimoto transmission cooler keeps ATF temps in check. Gearhead Automotive Performance fine-tuned the TCM and PCM.


So how does the truck run? Let’s just say Chad has a fourth-generation Mustang with a supercharged 347 stroker under the hood that collects dust in the garage now. Not only is the Super Duty faster than his other toy, but it blew past Chad’s 900-hp expectation on the dyno, laying down an impressive 1,089 hp and 1,911 lb-ft before the nitrous system was armed. On spray, the truck’s numbers jump to 1,243 hp and 2,211 lb-ft—more than enough to run low 10s if he can find adequate traction.

For now, Chad plans to enjoy the taste of getting kicked off the local drag strip for going too fast. In the long-term, he has plans to install a cage and enjoy his horsepower safely. Whether it’s making the dyno beg for mercy, hurting feelings at the track, or running up town for a quick errand, this XL trim F-250 will be in a much different line of work than was ever intended.

The battle-ready 6.4L Power Stroke in Chad Flynn’s ’08 F-250 begins with an externally-balanced crankshaft, anchored in place via the factory bed plate and swinging eight R&R forged-steel connecting rods fitted with ARP rod bolts. To endure elevated cylinder pressure, heat, and rpm, de-lipped and ceramic-coated MaxxForce 7 pistons with 0.120-inch valve reliefs from RCD Performance are employed. The heads are graced with Elite Diesel Engineering 145-ppi Stage 2 valve springs, cryo’d rocker arms, and H-11 head studs from A1 Technologies. Further valve train upgrades include Elite Diesel Engineering’s Stage 1X cam (with welded cam gear) and Stage 2 chromoly pushrods.
Billed as Elite Diesel Engineering’s most affordable path toward making 900 hp, Chad decided to give the company’s Raw Power compounds a try. The system’s first gulp of air comes by way of this fixed geometry atmosphere charger from Precision Turbo and Engine. It makes use of a 7-blade, 88mm compressor wheel, a 360-degree thrust bearing assembly in its center section, and mounts to a modified factory turbo base.
Chad’s secret to quick spool up lies in the Raw Power setup’s retention of the factory-based variable geometry BorgWarner. The high-pressure, journal bearing turbo is fitted with a larger, map groove compressor housing, a billet 11-blade compressor wheel with a 63mm inducer, and retains the OEM exhaust housing and VGT actuator. This charger produces two-thirds of the engine’s overall boost number.
With the compounds creating plenty of boost and no shortage of fuel being on tap, Chad knew his EGT readings wouldn’t be ideal. To combat high intake and exhaust gas temps, he installed an intercooler from Precision Turbo and Engine, which dropped incoming air temperature 150 degrees. The fabricated heat exchanger next to the intercooler is part of a fuel cooler relocate kit that came from Elite Diesel Engineering. It moves the fuel cooler off the top of the engine, works in conjunction with Chad’s fuel bowl delete, and cleaned up engine bay clutter significantly.
To keep the engine safe and the turbos alive, Chad lives by one rule: keep drive pressure below 100 psi. The combination of 44mm TiAL and 46mm Precision external wastegates allows him to do just that. And to fine-tune boost by controlling how quickly the gates open, Chad uses a pair of Speedaire regulators he mounted along the firewall. Fellow 6.4L gurus J.D. Gleason and Dustin Woodhouse were instrumental in helping Chad get both gates configured exactly where they need to be.
For that little something extra, a Nitrous Express system brings another 200hp worth of oxygen to the table. The single stage kit utilizes a .120 jet plumbed into the cold-side intercooler pipe, a 15-pound bottle mounted in the bed, and is wired to a wide-open throttle switch.
To eliminate wheel hop during boosted, four-wheel drive launches, Chad installed RCD Performance’s front four-link system. Doing away with the factory radius arms, RCD’s beefy setup employs 1/4-inch thick, low carbon steel brackets, 1.5-inch outer diameter, 0.250-inch wall seamless DOM tubing for the bars, and high-strength Kevlar-lined Heim joints at all pivot points.
With big horsepower being Chad’s principle concern, he went all out on the injection system. Elite Diesel Engineering’s dual K16 system added a second, belt-driven highpressure pump to the equation, and a set of Stage 2 ported rails provide 25-percent more capacity. Under the valve covers, you’ll find a set of 150-percent over injectors from RCD Performance that are capable of supporting 1,400 hp should Chad ever seek future growth.
Making sure the K16s are well-fed, Chad put together his own competition-ready lowpressure fuel supply system. After diesel leaves the Bean Machine sump he installed in the factory tank, it flows to a water separator via ¾-inch fuel hose on its way to an Aeromotive A1000. From there, it leaves the 2-micron fuel filter and heads to the distribution block on the engine through 5/8-inch hose.
When it came time to put the power to the pavement, Chad knew he needed a transmission that could hold up to abundant low-rpm torque and firm shifts. In once again reaching out to Elite Diesel Engineering, he received a race-ready Stage 5 version of the 5R110W TorqShift. The Aermet input shaft, 300M intermediate shaft, billet overdrive planetary and Low-Reverse hub make it one of the strongest in the industry, and its increased count, Raybestos clutches and a four-disc DPC converter are top-of-the-line as well.
With 1,100 hp and 1,900 lb-ft of torque on tap on fuel alone, the 305/45R22 NT420Ss definitely have their work cut out for them in trying to maintain traction, but they do the best they can. The all season Nitto tread is mounted to 22×11-inch Hostage wheels from Fuel Off Road.
Things get complicated with high horsepower. To help him both monitor and log key parameters, Chad installed a Banks DataMonster along with added sensors to keep an eye on each turbo’s boost and drive pressure production. Banks’ groundbreaking gauge proved invaluable while dialing in the turbo system’s wastegates
No fancy race seats here—just the original bench seat that came standard on an XL trim Super Duty. To be sure, the truck is still used to do work. It just has a different job to do now.


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