go all out. Obviously, Reece chose the latter route. 390 CI DURAMAX
After consulting with the folks at Dermody Diesel, the decision was made to try something unique. A short-stroke engine was put together soon afterward by using some of the best parts in the industry.
Foundationally, the Duramax sports a short-stroke (3.75-inch) Callies Ultra Billet crankshaft that’s secured by ARP main studs. The crank swings a set of Wagler Competition Products’
forged-steel I-beam rods, which mate to 0.020-inch-over Ross Racing forged-aluminum pistons with 0.095-inchdeep valve pockets and Hemi-style wrist pins. For improved durability where the heads meet the block, the block was machined to accept O-rings. A Diesel Technology Source Dominator series standard firing order camshaft, Wagler pinned oil pump and billet water pump, and a PPE oil pan rounded out the parts list for the built bottom end. HIGH-FLOW HEADS
Above the Wave-stopper Mahle head gaskets sits a set of Dominator series factory-based cylinder heads from Diesel Technology Source. They’ve been CNC ported, fitted with dual valve springs that utilize titanium retainers, feature Wagler billet rocker arm bridges, Wagler 3/8 x 0.135-inch wall chromoly pushrods and anchor to the block by way of ARP Custom Age 625+ head studs. For added bling, the factory valve covers were ditched in favor of Wagler’s billet 6061 aluminum valve covers. FUEL AND AIR FOR FOUR-DIGIT POWER
Sizing a pair of turbos that afforded solid drivability without running out of steam at high rpm, Reece and Dermody settled on an S366-over-s480 compound arrangement—but not just any old S366 or S480: Both turbos began life as SX-E models from Borgwarner but were tweaked and tested to move roughly 15 percent more air. They are pieced together with intercooler piping, a T4 pedestal, Y-bridge and select other components from HSP Diesel. These compounds produce 85 to 90 psi of boost at full tilt. Healthy, 250-percent-over injectors and a 14mm CP3 from S&S Diesel Motorsport highlight the fuel system mods, with a 260 gph FASS system and RCD Performance sump kit supporting the effort. RACE-READY ALLISON
Transferring a dyno-confirmed 1,620 lb-ft of torque to the rear wheels is a full billet race Allison 1000 from Diesel Technology Source. The six-speed employs a host of billet hard parts, including the input, output and intermediate shafts, as well as a billet
The atmosphere charger in the two-stage arrangement is a T6 flange S480 Sx-e-based unit with a slightly re-worked version of Borgwarner’s forged-milled wheel compressor wheel, a larger map groove, machined 88/96mm turbine wheel and a 1.32 A/R exhaust housing. It sends boost to the valley charger via 3-inch intercooler piping, while a 3-inch hot pipe feeds it exhaust gases (both of these came from HSP Diesel). Convenient for daily- or street-driven Duramaxes, the parts supplied by HSP Diesel also allowed the charger to be mounted without relocating the passenger’s-side battery.
With a 14mm CP3 from S&S Diesel Motorsport to feed, a 260 gph Titanium series FASS system got the call. It pulls fuel from the tank through an RCD Performance sump. On the other side of the stroker pump, a set of 250-percent-over injectors (also from S&S Diesel Motorsport) offer enough capacity to support roughly 1,400 hp at the crank.
Backing up the potent Duramax is a full billet race version of the six-speed Allison. Built by Diesel Technology Source, it’s graced with billet input, output and intermediate shafts, along with a billet C2 hub, billet P2 planetary and a Goerend extra-capacity transmission pan. Efficient power transfer begins with a model R billet stator triple disc converter from Goerend. Its 2,200 rpm stall speed is well-matched with the truck’s S366/S480 compound arrangement, which results in good overall drivability.
The built Allison’s “hands” are full harnessing the 1,700 lb-ft of torque that are trying to be squeezed through it, so the last thing it needed was a cooling problem. To make 100 percent certain the A1000 never boils over, an Xtrude auxiliary transmission cooler with double-stacked cores from BD Diesel was plumbed into the Allison’s cooling circuit and mounted to the frame rail.
The truck’s immaculate interior makes it hard to believe it’s seen more than 190,000 miles of use. Aside from the aftermarket steering wheel cover, gauges and a few discreetly mounted up-fitter switches, the four-door cab looks the same way it did when it was built more than 11 years ago.
When the occasion calls for it, Reece can bypass the TCM and take converter lockup into his own hands, thanks to the use of an Allilocker from Fleece Performance Engineering. Rather than use the ashtray in the dash to mount his DSP5 switch, Reece uses it to stow the Allilocker when it’s not in use.
Five ECM calibrations—custom-tailored through the use of EFI Live—are available via this DSP5 switch on the dash. The Custom Tuning Team files range from roughly 700 rwhp to 1,000 rwhp. And, thanks to the 250-percentover injectors (and 14mm CP3), the truck’s four-digit horsepower is achieved with little duration being required to pull it off.
Through the use of an Edge CTS, Reece keeps tabs on both desired and actual rail pressure, along with supply pressure from the FASS system and EGT. The two Auto Meter Cobalt series A-pillar gauges monitor boost pressure. The 0–60 psi gauge on the bottom shows how much boost the atmosphere charger is contributing, while the top 0–100 psi gauge displays combined boost from both turbos. Reece tells us that at full load, the needle on the top gauge taps 90 psi.