68RFE 6.7L Dodge Cummins Mega Cab

Derrick Barney’s 1,400HP, 68RFE Shifted ’11 Mega Cab

When a rod left the block of his 6.7L Cummins a few short years ago, Derrick Barney never could’ve imagined that he would soon own one of the most powerful—and reliable 68RFE equipped Rams in the country. But that’s exactly what you’re about to read about in the following pages. He had a new engine built, and has added dual CP3’s, upsized injectors, and went from an S472 to a single S480 in his un-ending search for more power. Along the way, he’s dealt with the trials, tribulations, and (of course) monetary setbacks that come with st icking it out with Chrysler’s notorious six-speed automatic. However, if you cross paths with him, he’ll tell you it was worth every second.

Fresh Start, Stronger Foundation

Starting with a fresh block, Derrick pulled out all the stops in making sure a hard-part failure never struck again. The mains are now tethered together courtesy of a Gorilla Girdle and ARP main studs from Industrial Injection while the rest of the short-block consists of Carrillo rods mated to ceramic coated factory replacement pistons. The head was transformed into one of Freedom Racing Engine’s Street HD units, with hardened and oversize valve seats, 105-lb valve springs, and threaded freeze plugs. ARP Custom Age 625+ head studs fasten it to the block.

2nd-Gen Turbo Swap, S480 and Competition Manifold

When Derrick initially took the factory Holset VGT out of the equation in favor of Stainless Diesel’s second-gen turbo swap kit, he didn’t jump straight into running the S480. Rather, after running one of Stainless’ T4 S472 chargers (a 72/87/1.0 that allowed 894-rwhp to be made on the rollers), he wanted to take things even further. The switch to the current 5-blade S480, an 80/96/1.15 with a T6 foot, brought more than 200 more ponies into the picture. Now his biggest problem is the fact that the truck runs out of road long before it runs out of air. Complementing the S480 is a Stainless T-6 24-valve Competition exhaust manifold, which—with its full-length 1.65-inch diameter internal runners—makes spool up a non-issue and the truck extremely drivable on the street.

Dual CP3’s and 350hp Injectors

Adequate rail pressure is always on tap thanks to H&S Motorsports’ dual high-pressure fuel kit. Both the factory location CP3 and the second, belt-driven pump are stock 6.7L Bosch units. A ported rail supports the effort and injectors fitted with 152-percent over Industrial Injection nozzles handle in-cylinder fuel delivery. Given the nozzles’ size, which Industrial also refers to as its 350hp units, just under 1,100-rwhp can be made on fuel with a CTT Tuning that calls for just 2,250 microseconds worth of duration. Feeding the CP3’s all the low-pressure fuel they need is left to a 165-gph AirDog II system.

Sticking With The ‘68

Every ’07.5-present Dodge Cummins owner that’s pursued horsepower in conjunction with the 68RFE platform has a story to tell, and Derrick is no different. Back before the truck lost all of its innocence, Derrick campaigned a Signature Series 700 from RevMax, which tolerated three years’ worth of abuse before requiring some TLC. He then upgraded to RevMax’s Signature Series 850 for a bit, but had to regroup once again when the stakes went even higher. At the present time, there is a host of one-off and even prototype parts stacked inside the transmission case. Pieced together at White Knuckles Garage, the 68RFE features a custom-machined 300M 4th hub and RevMax XR input drum from Randy’s Transmissions, a billet-steel center support, a maraging steel input shaft, and Randy’s Baby Maker 1000 valve body. The torque converter is a billet, triple-disc unit from RevMax, with a 2,200-rpm stall speed.

Trail-Blazing

Countless 6.7L Cummins owners bid the 68RFE farewell long before they pursue the kind of power Derrick’s Mega Cab is making, the most common reason being the questionable reliability of a built ’68 given the amount of money spent. Luckily for us, Derrick does things differently than most… and the battle-tested six-speed in his Mega Cab has had 1,436 hp and 2,578 lb-ft of torque squeezed through it and lived to tell the tale. On top of that, it’s also been subjected to more than 20 boosted four-wheel-drive launches (in first gear, no less) and gone up against some pretty nasty streetcars on the local no-prep scene. Derrick credits longtime horsepower junkie and close personal friend, Stephen O’Neal of White Knuckles Garage, for building him a transmission capable of surviving so much abuse. Every time he hits the street, dyno, or track, Derrick and his 8,100-pound Mega Cab prove that you can have your cake and eat it, too in the world of the infamous 68RFE.

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After a factory rod left the block on a trip to Florida, Derrick Barney made sure that type of catastrophic failure would never happen again. His new 6.7L Cummins was assembled with a Gorilla Girdle from Industrial Injection and 12mm ARP main studs, Carrillo rods attached to ceramic-coated stock bowl pistons, a 188/220 cam from Hamilton, and a street head from Freedom Racing Engines. The head, which was fitted with hardened and oversize valve seats, 105-lb valve springs, and threaded freeze plugs, is anchored to the block by way of ARP Custom Age 625+ head studs.
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Surprisingly, Derrick swears the T6 S480 spools as quickly as his previous T4 S472 did, and his exhaust manifold plays a key role in its responsiveness. Stainless Diesel’s T-6 24-valve Competition unit features CNC-ported, ultra-smooth, 1.65-inch diameter ports and full-length internal runners all the way to the collector foot. For a bit of underhood bling, Derrick also added one of Stainless Diesel’s billet-aluminum valve covers. A coolant bypass kit from Fleece Performance Engineering safeguards the rear cylinders from seeing excessive heat.
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The T6-flanged Stainless Diesel S480 is a long way from the original HE351VE Holset Derrick’s truck left the factory with, and it’s a major part of his Mega Cab’s 1,100hp fuel-only number. Its 5-blade, 80mm compressor forces a ton of air into the 6.7L Cummins, while the 96mm turbine wheel and 1.15 A/R exhaust housing provide plenty of flow up top. With the truck under load in sixth gear, Derrick has seen a boost as high as 68-psi.
AirDog II , ½-inch hose, 165-gph pump, FASS sump pump
The trusty old AirDog II sits tucked up behind the driver-side rear door and ensures plenty of low-pressure fuel supply makes it to the CP3s. Utilizing a ½-inch hose, the 165-gph pump pulls fuel from a FASS sump pump installed in the factory tank.
Modified RevMax XR input drum, a billet-steel center support, 300M billet 4th hub, a maraging steel input shaft, Randy’s “Baby Maker 1000” valve body, 2,200-rpm stall triple disc converter from RevMax
Having been through several 68RFE automatics now, the current version residing in Derrick’s Mega Cab has been the toughest, by far. It was built with key parts (some of them even prototype pieces) from RevMax and Randy’s Transmissions, a few of which being a modified RevMax XR input drum, billet-steel center support, 300M billet 4th hub, a maraging steel input shaft, and Randy’s “Baby Maker 1000” valve body. A 2,200-rpm stall triple-disc converter from RevMax works extremely well with the big single charger and is a vital part of the truck’s sound drivability.
Pair of stock displacement CP3’s, H&S Motorsports dual high-pressure fuel kit, a ported fuel rail to maintain rail pressure. 152-percent over (350hp), extrude honed nozzles from Industrial Injection
A pair of stock displacement CP3s, courtesy of an H&S Motorsports dual high-pressure fuel kit, work in conjunction with a ported fuel rail to maintain rail pressure. They support a set of injectors that’ve been equipped with 152-percent over (350hp), extrude honed nozzles from Industrial Injection.
Heavy duty traction bars from Wehrli Custom Fabrication, greasable Johnny Joints from Currie Enterprises,
Keeping the rear AAM 1150 located is a set of traction bars from Wehrli Custom Fabrication. The heavy-duty bars attach to both the frame and axle via weld-on mounts, feature greaseable Johnny Joints from Currie Enterprises, and have held up very well to salty northern Illinois winters.
A-pillar gauges and a dash-mounted iPad
A-pillar gauges and a dash-mounted iPad are the only noticeable aftermarket add-ons in the Laramie interior. Most of Derrick’s parameter monitoring takes place on the big screen, where he is also able to navigate through a host of custom-tailored calibrations from CTT Tuning. The biggest file in his arsenal calls for approximately 2,250 microseconds of injector duration, which is good for four-digit horsepower on fuel and more than 1,400 hp on spray.
Carbon Fiber look 5-inch stack with exhaust kit custom-built out of stainless steel piping
As proof that you can still pull off the bed stack look, Derrick’s fourth-gen sports a 7-inch carbon fiber version from Old Skool Fab that seamlessly protrudes out the tonneau cover and stops at the top of the cab. The exhaust system between the stack and S480 (including the downpipe) is all 5-inches in diameter and was custom-built out of stainless steel piping.
dyno at White Knuckles Garage
Already having proven itself on the dyno at White Knuckles Garage with a near-1,100hp effort on fuel, Derrick couldn’t help himself at the 2020 Scheid Diesel Extravaganza and strapped the Mega Cab to the rollers. With the 68RFE locked in fifth gear and an open bottle of nitrous in the mix, the truck put down a jaw-dropping 1,436 hp and 2,578 lb-ft.
8,100-pound 2008 Dodge Ram Cummins Drag Truck
When Derrick swaps out the Nittos for 28-inch slicks and goes racing at his local no-prep events, this is the view a lot of hot-running street cars see: the rear three-quarter of his 8,100-pound Ram. Confidant, wrencher, and White Knuckles Garage owner Stephen O’Neal thinks the truck could go high 6’s or maybe even 6.70 in the eighth-mile. Who knows, if the tough-as-nails 68RFE keeps holding, Derrick might just try it!
American Force Banshee SS wheels with Nitto NT420S 305/35R24 tread
If you ask us, it’s the aesthetic appeal of the American Force Banshee SS wheels that set the truck off most. The polished 24×12-inch wheels feature a 40mm offset, 5-inches of backspacing, and a 6.5-inch lip. They’re wrapped in Nitto NT420S 305/35R24 tread, and each tire has its work cut out for it in terms of maintaining traction—even in four-wheel drive.

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