A 1,500 HP Stock-Appearing King Of All Sleepers

Mark Rojee’s Stock-Appearing, 1,500 HP ’18 Ram

What do you get when you take a Hemi junky’s half-ton Ram away from him and give him a -ton Cummins? If you’re Mark Rojee, you turn your new workhorse into a 1,500hp daily driver that’s just as much of a terror on the street as it is at the track. Five years after purchasing his brand-new ’18 Ram 2500, an Enforcer Series 6.7L Cummins dwells under the hood, a 48RE sits in place of the 68RFE, and the full interior crew cab runs 6.40s in the eighth mile. But by far the best part about Mark’s fourth-gen is its retention of the factory 20-inch wheels, the presence of the half-worn all-terrains, and the stock tailpipe. Trust us, it doesn’t get any more inconspicuous than this.

It’s a common sight for many high-powered common-rail Rams these days: a D&J Precision Machine Cummins under the hood. The Enforcer series version dwelling in Mark Rojee’s ’18 Ram 2500 is based on a cast-iron block that’s been sleeved, fitted with a deck plate, fire-ringed, and equipped with an HD girdle, X-beam rods, and cast-aluminum pistons. A billet flat tappet cam, Hamilton billet lifters, and 7/16-inch diameter pushrods make for a rock-solid valvetrain.

Seeing no need to reinvent the wheel, Nathan had Dermody Diesel Performance keep things simple yet economical and effective when reinforcing the bottom end of his 2006 LBZ. Under all the Illusion Cherry powder-coated intercooler and intake plumbing, there’s a competition-prepped short-block packing an externally balanced crank, ARP main studs, Wagler forged-steel I-beam connecting rods, and cast-aluminum stock compression Mahle Pistons. To ensure sufficient oil pressure is always on tap under load, a shimmed oil pump from Wagler sits in place of the factory unit, while Cen-Pe-Co Super High-Performance engine oil circulates throughout the engine.

As the owner of Village Garage and Mahky’s Performance, and with a background in the Hemi world, it makes sense that Mark would own a Ram—but why would he want to build a 1,500hp Cummins? Well, as it turns out he works on diesel, too, and who wouldn’t want a truck that can do it all? “The plan from the beginning was to daily drive it, make big power with it, and tow with it,” Mark tells us. “The truck has been making big power since about 14,000 miles, back when it had a single S480/96/1.15 on it and the stock engine that I eventually blew up.”

Sleeved & Deck-plated 6.7L

After reading the aforementioned factory 6.7L, Mark contacted D&J Precision Machine and rocked one of its Performance series Cummins power plants for a while. Recently, however, he stepped up to an Enforcer—the same engine that’s won Ultimate Callout Challenge two years running. The cast-iron 6.7L block is sleeved, cut to accept fire rings, and topped off with a deck plate. It sports a factory crank secured by way of a girdle, which spins a set of D&J X-beam rods capped with cast-aluminum pistons. A Stage 3 (fire-ringed) head with oversize valves, 115-lb valve springs, and titanium valve spring retainers flows nearly double what the factory unit did and fastens to the block courtesy of 9/16-inch ARP head studs.

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Big air calls for big fuel, and Mark held nothing back in that department. To support a set of 250-percent over injectors from S&S Diesel Motorsport, an S&S 14mm CP3 was installed. The high-speed stroker pump provides for high-rpm fueling, and the potent common-rail system is dialed in through the use of EFI Live tuning software.

Tucked up along the driver-side frame rail sits an AirDog II-4G lift pump system, which pulls the fuel from the factory tank. The 200 gph system feeds fuel to the 14mm CP3 through the ½-inch hose, and at 15 psi. Its high mounting location conceals 90 percent of the filters from view, further adding to the truck’s inconspicuous look.

A sizable set of S400-based compounds feed 110-psi of boost through a factory intercooler, and ultimately the Enforcer engine. Sourced from Forced Inductions, the atmosphere charger sports a 91mm compressor, a 104mm turbine, and a T6 inlet, 1.32 A/R exhaust housing. The primary unit (also supplied by Forced Inductions), makes use of a 72mm billet compressor, an 87mm turbine, and a spool-friendly 1.00 A/R exhaust housing. The S472 mounts to a T4 Steed Speed exhaust manifold and a 45mm TurboSmart external wastegate that’s not visible here routes excess drive pressure into the hot pipe of the S491.

Compounds, Nitrous, And 110-psi Of Boost

Anytime an engine with a high-flow head sees a triple-digit boost, you know some serious horsepower is being generated. In conjunction with a shot of giggle gas, Mark’s compound arrangement makes more than 1,400 hp possible at the wheels. It begins with a 91mm atmosphere charger from Forced Inductions, complete with a 104mm turbine wheel residing in a 1.32 A/R exhaust housing with a T6 inlet. The primary turbo, also a Forced Inductions unit, hang from a T4 Steed Speed exhaust manifold and boasts a 72mm compressor, an 87mm turbine, and a 1.00 A/R exhaust housing. Two stages of boost combine with a potent shot of nitrous before passing through the factory intercooler.

S&S And AirDog Fueling

A healthy dose of fuel is present in Mark’s nitrous-assisted, 1,500hp equation and he went with S&S Diesel Motorsport to get him where he needed to be. It starts with a 14mm stroker CP3 to maintain adequate rail pressure for a set of 250-percent over injectors to use. Of the high-speed variety, the high-pressure pump is good for fueling well beyond 3,000 rpm. A 200-gph AirDog II-4G system keeps the low-pressure fuel supply clean and consistent. It pulls the fuel from the factory’s 31-gallon tank. Well-versed in EFI Live software, Mark uses it—in conjunction with the factory ECM—to dial in the injection system.

Believe it or not, the ’18 Ram’s suspension is completely stock, aside from the addition of air springs in the rear. Though Mark had initially installed them to aid the truck while towing, he soon found that leaving the minimum amount of air in them (5 psi) helped curb the extreme weight transfer that was costing him precious tenths in his 60-foot times. The axles are 100 percent untouched, and sport 3.42 gears, which Mark believes help both load the engine harder and ensure the all-terrains don’t break traction during boosted four-wheel drive launches.

A 48RE With All The Right Parts

It didn’t take long for Mark’s aspirations for a big power to outrun what the 68RFE platform could support, so he converted to a 48RE and pressed on. “I was trying the whole ‘big power, 68RFE thing’ but it wasn’t working out well,” he told us. “So I swapped to a 48RE that I built myself.” Input, intermediate, and output shaft upgrades, Raybestos GPZ clutches, and a 2,300 to 2,500-rpm stall triple disc Goerend Converter and 12-bolt flex plate fortify the four-speed, while a high-pressure valve body from Goerend complements its converter. From inside the cab, Mark uses an Anteater Pro to program and command the 48’s shift points as well as a lockup.

For an extra kick in the eighth mile, which happens to help the full interior Ram turn out blazingly quick, 6.4-second eighth-mile elapsed times, Mark relies on one big hit of nitrous. Using a single, .123 orifice Nitrous Express solenoid, wired to a wide-open switch, and utilizing a .136 jet, Mark adds N2O to the equation pre-intercooler. As many drag racers have found, introducing spray before the intercooler gives the nitrous more time to work its cooling magic prior to entering the engine.

Although Mark gave it a go with the 68RFE initially, it didn’t take long for his power goals to end the six-speed life. A 48RE swap was in order, but not just any ’03-’07 four-speed. Pieced together at his place of business, Village Garage in Marstons Mills, Massachusetts, Mark included a Sonnax 35-spline input shaft and 300M intermediate, a TCS 29-spline output shaft, GPZ clutches throughout, and a triple disc, 2,300 to 2,500-rpm stall converter and valve body from Goerend Transmission. So far, his 48RE has had no issues holding up to the truck’s 1,400-plus horsepower at the wheels, which is accompanied by 2,000-plus lb-ft of torque.

6.40s In The Eighth

All of the above, combined with Ram’s factory suspension, axles, tire size, and wheels, has culminated in 1.5-second 60-foot intervals and blazingly-quick 6.40s in the eighth mile at more than 110 mph. Spotting the stock wheels and tailpipe yet also noticing the “6.70” written on the windshield definitely caught our eye. Sure enough, Mark’s crew cab short bed didn’t disappoint, immediately letting us know some very big power was concealed under the hood. Our first encounter with Mark and his Ram was highlighted shortly after that when the truck went 6.42 at 110 mph—the quickest the truck would storm the ‘660.

Other than the Anteater Pro visible on the center console, you would never know this was the interior of a low 10-second, late-model Ram—and that’s exactly the way Mark wanted it. Inside and out, his fourth-gen was purposely left inconspicuous in appearance, with all kinds of power being produced under the hood and sent to the factory wheels.

Yes, it gets driven. According to Mark, he put nearly 100,000 miles on the truck in less than three years. Incredibly, as he was unable to leave well enough alone, the late-model Ram has been making big power since the 14,000-mile mark. Early setups included rocking a single S480 the original 6.7L’s stock bottom end, an engine that Mark eventually blew up.

An Anteater Pro from Firepunk Diesel allows Mark to program the shift points of the 48RE to his liking. The stand-alone transmission controller also provides full control over converter lockup and features Overdrive on/off operability.

Now for the sad part. A recent front driveshaft failure caught a nitrous line during a full-effort eighth-mile pass and started the truck on fire. The damage was extensive and Mark decided not to rebuild. However, he did order a ’22 Cummins—and he plans to do the exact same thing to it. With absolutely no reason to doubt Mark’s knack for building the ultimate sleeper, be on the lookout for a factory wheel and tire fifth-gen packing 1,500 hp and racing at a diesel event near you in the spring of 2023.