Alan Watson’s rare, DT360 International-swapped Super Duty packs a Bosch P7100, a ball bearing turbo, and turns out 850 hp.
You read that right. The inline-six under the hood of this ’05 F-350 is no Cummins. It’s one of those old-school Internationals you might’ve heard about. Not the coveted DT466, but a DT360—a smaller sibling that enjoys the same robust design. Like the DT466, the iron block and head, wet-liner I-6 was developed in the late 1960s, officially debuted in 1971, and requires very few hard-part upgrades in order to survive big horsepower. After Alan Watson’s “bulletproofed” Power Stroke let him down for the final time, he swore off the 6.0L forever. One phone call to Carson Stauffer later, and Alan was convinced a DT360 conversion was the path he’d be taking with his Super Duty.
With a take-out engine sourced—and with the help of a close friend who knows the 360ci IH powerplant inside and out—Alan set to work piecing the 5.9L together. Fourteen months later, and with the likes of Carson Stauffer Diesel, Scheid Diesel, Tater Built Turbochargers, and Kenny’s Pulling Parts & Machine all involved in the project, the engine sports a P-pump on one side, a 68mm turbo on the other, and transfers power through the original ZF-6 transmission. It also belted out more than 850 hp on the dyno, which is more than enough power to get Alan’s crew cab dually up and moving. If you ask us, Alan’s Ford proves the DT360 is one heck of an alternative to the average, everyday Cummins swap.
This is what the International DT360 looked like the day Alan brought it home. The engine was sourced from a friend and fellow worker in the logging industry. The 1989 model year engine, which was using oil, was plucked out of the International S1700 service truck it was powering for more than three decades. But with plans to tear the DT360 apart and rebuild it from the ground up, its oil consumption problem didn’t concern Alan in the least.Built with the help and advice of Elmer Stone, a 300 and 400 series IH engine guru with a background in tractor pulling, the engine was pieced together with utmost longevity in mind. The factory crankshaft, main bolts, and forged-steel connecting rods remain, although the reused rods were treated to fresh rod bolts and polished to remove any possible stress fracture points and to ensure each weighed the same. OEM-based, valve-relieved cast-aluminum pistons are equipped with a gapless (Total Seal) second oil ring as well as a custom oil groove for added lubrication at higher rpm and horsepower. The camshaft is factory and, as you can see here, its gear has been tack-welded into place in order to keep it from walking or pushing off the camshaft. Over on the right, you’ll notice a red adapter and hub—a Carson Stauffer product developed to run a P7100 on the DT360 and DT466 engines.For a bit of added overkill, a set of OEM wet sleeves were cut to accept fire-rings. Combined with a factory head gasket (less the wire rings) and fresh head bolts torqued to 180 ft-lb (there are six fasteners per cylinder), the head will likely never lift off the block—even at 850 hp. The head itself benefits from tack-welded rockers and high rev valve springs from Carson Stauffer Diesel. High strength pushrods (also from Carson Stauffer Diesel) link the valves and camshaft together.To size the right turbo for the DT360, Alan turned to Tater Built Turbochargers and settled on this unit. Garrett G42 based, it’s a charger the company calls its S400 replacement. It makes use of a billet, 7-blade 68mm compressor wheel, a 9-blade 75mm turbine wheel inside a 1.01 A/R exhaust housing, and boasts a dual ball bearing center cartridge. It’s said to spool quicker than the BorgWarner S464/83/.90 unit, a popular journal bearing turbo in the Cummins segment. Alan reports it’s very drivable, even in his manually shifted application.The turbo hangs from a factory DT360 exhaust manifold, which is of the T4 divided variety. Notice the air guillotine in front of the turbo’s compressor. Killing the engine’s air supply is a safety precaution (as was supplying the P7100 its own, self-contained oil source) Alan opted for just in case the P-pump ever unexpectedly sticks the rack. Also notice the V-band outlet on the turbo’s compressor housing, a welcomed rigid connection point being that the Tater Built unit produces a healthy 55 psi of boost at full tilt.Things get interesting on the intake side of the engine thanks to this piece. In order to run the bulky Bosch P7100, the engine’s original intake manifold had to be scrapped in favor of this one—a unit off an agricultural application. It was used on the D360 (non-turbo) engine found in International 766 and 886 farm tractors. With a bit of grinding (on both the manifold and the P7100’s AFC housing), Alan was able to gain a slim, 0.035-inches worth of clearance between the AFC and manifold.Scheid Diesel supplied the custom bent, .093-inch injection lines spanning from the P7100 to the injectors. The injectors themselves were also built by Scheid and benefit from 4 x 0.018-inch nozzles. Forward of the front cover, you can see some of the pieces Carson Stauffer developed to furnish a DT360 with a serpentine belt system. When all was said and done, Alan was able to reuse his 6.0L Power Stroke’s A/C condenser and alternator, while a tensioner and idler pulley from a 6.4L application became part of the serpentine system.Yanked from a 12-valve 5.9L Cummins serving duty in a dump truck, P-pump guru, Dakota Grant, worked his mechanical magic on the P7100. The 12mm pump has been graced with a quick-rate cam, DLC coated pins and rollers, 215 hp plungers, 0.120-inch delivery valve holders, and full cut delivery valves. Dakota also fine-tuned the AFC and installed a custom-tailored fuel plate. On the test bench, the pump proved capable of flowing as much as 650 cc’s, but in street trim it’s set to roughly 350 cc’s. The P7100’s fuel supply comes courtesy of the same FASS system that once served time feeding 65-psi of pressure to the injectors in Alan’s 6.0L Power Stroke.Alan (right) and Elmer Stone (left) teamed up on the DT360 engine. As a full-time diesel mechanic since the 1990s and someone who’s been tinkering on these engines for 50 years—including in competitive tractor pulling—Elmer knows his way around the 300 and 400 series IH engines. Undoubtedly, many of his secrets made it into Alan’s build. With this kind of company, it’s no wonder Alan and Elmer are also in the process of piecing together a Hot Farm pulling tractor.Carson Stauffer Diesel invested a lot of R&D hours into making the DT360 swap possible, and this is another reflection of their efforts. Integrating the DT360 with the truck’s factory transmission called for this adapter plate, made specifically to accommodate the ZF-6 manual. Efficient power transfer is made possible thanks to a triple-disc clutch from Kenny’s Pulling Parts & Machine. Despite the competition-ready nature of the sintered iron clutch, Alan told us the pedal feel is similar to stock and that the truck is still running factory hydraulics.The moment of truth for Alan’s DT360 came on the engine dyno at Carson Stauffer Diesel. There, bolted to the company’s Land & Sea unit, the freshly built International made 851 hp and 1,300 lb-ft of torque. Those numbers were achieved with the engine timed 36 degrees BTDC and the P-pump moving roughly 525 cc’s of fuel. The DT360 also saw 5,300 rpm that day—a one-note song Alan won’t soon forget. For daily-driven use in Alan’s F-350, timing was backed off to 26 degrees and 350 cc’s, an arrangement he says still turns out roughly 700 hp.This is the lucky recipient of the potent DT360, Alan’s ’05 F-350 he’d purchased with 150,000 miles on the odometer. To be sure, Alan did the whole high-horsepower 6.0L Power Stroke thing, and he did it for quite a while before throwing in the towel. The job of dropping the DT360 into place and then making everything work was left to Carson Stauffer Diesel. In the company’s care, Jason Stauffer performed most of the work, including fabrication, customization, and wiring. With the Ford PCM still in use and a helping hand from the folks at SwapHelper.com, the truck’s factory gauge cluster, tach, and even cruise control work just like they did before the swap.It might be 4-inches shorter in length than a DT466, but it’s still 4-inches longer than a 5.9L Cummins. Needless to say, it was a tight fit squeezing the DT360 into the Super Duty’s engine bay. The firewall went untouched, but the radiator and intercooler had to be relocated 2-inches closer to the grille. The radiator (equipped with six electric fans rather than the bulky factory fan clutch setup) and degas bottle are reused 6.0L components, while the intercooler is an aluminum end-tank unit off of a 7.3L. Other fitment issues called for cutting down the truck’s engine cross member to clear the DT360’s oil pan and Jason Stauffer fabbing up a pair of custom motor mounts. Jason also fabricated the intercooler piping shown here.For a bit of dress-up and to pay homage to the master mechanic behind the build, Alan had the hot and cold-side intercooler pipes powder coated a deep blue and also had custom graphics added to a polished core support cover thanking Elmer Stone for all of his help. Shain Custom Signs & Decals handled the graphics in neaby Racine, Ohio, while Alan’s friend, Josh Caldwell, took care of all the powder coating. But Alan didn’t stop there. Badges calling attention to the International under the hood were added to the cowl, the front clip, and the bottom of each of the truck’s front doors. As we went to press, he was in the process of ordering a shift knob with the International logo on it.It’s a long way from the original power rating it was given back in 1989, but Alan’s DT360 should still last indefinitely—even at 700-plus horsepower. Perhaps this is the biggest advantage a 5.9L International holds over its B-series competition. Like the legendary DT466, it was overbuilt in pretty much every conceivable way. “The big thing with the DT is that you can have mainly stock hard parts, make 800 hp or more, and the engine will live forever,” Alan says. “You can’t really do that with a 5.9L Cummins.”
