In our final installment of our brand-specific dyno days, we finish strong with some of the most powerful trucks we have rolled yet. For those of you who have been following this series, you know that we did a 7.3-liter Power Stroke dyno day when we launched the magazine, and then followed that up with a 6.6-liter Duramax dyno day. Now, we have the all-mighty six-cylinder Cummins.
For the first time in this series, we break the 1,000 horsepower mark. We had a few trucks that should have, but for whatever reason, they were not able to break into the four-digit realm.
This is also the first time that we did not hold the dyno day at our corporate headquarters in Southern California. Instead, we headed east to the Lomghorn state (Texas) where we took over Truck Source Diesel’s (TSD) dyno. They were gracious enough to run their Dynojet 224XLC all day for us and play host to five very strong trucks that represent the evolution of Cummins power!
The Evolution
- Bore: 4.02 inches
- Stroke: 4.72 inches
12 Valve
- Horsepower ranges: 160 hp to 215 hp
- Torque range: 400 lb-ft to 440 lb-ft
24 Valve
- Horsepower ranges: 215 hp to 245 hp
- Torque range: 420 lb-ft to 505 lb-ft
Common Rail
- Horsepower ranges: 235 hp to 325 hp
- Torque range: 610 lb-ft to 850 lb-ft
6.7-liter
- Bore: 4.21 inches
- Stroke: 4.88 inches
- Horsepower ranges: 350 hp to 385 hp
- Torque range: 460 lb-ft to 900 lb-ft
It is pretty amazing to consider that an engine initially developed in the early ’80s is still in production in the automotive industry. There have been many changes within the industry that have resulted in most powerplants having been redesigned or replaced a number of times. While the 5.9-liter Cummins has undergone a number of updates and revisions over the years, the basic architecture remains the same. In fact, there are a number of parts that can be swapped between different revisions, indicating the commonality (in fact, we recently did a story on a 6.7-liter Cummins that was converted over to a VE rotary injection pump from the early ’90s).
The initial Cummins is known as a 12-valve due to its two-valve per-cylinder design. These engines came with a VE rotary injection pump and piston pump (P-pump), depending on the year. The first major revision to the engine came in 1998 when emission regulations started to play a major role in engine performance.
The update/redesign called for a new cylinder head with four valves per cylinder, a rotary injection pump (VP44) with electronic controls, and some other basic emissions equipment. These engines are known as 24-valve engines and they were produced from 1998 to 2002. They are also probably the noisiest of the different generations.
By 2003, Cummins had switched over to a common high-pressure fuel rail and operated the injectors via electronics. These engines received a number of revisions, but the fuel rail change gave them a new name, Common Rail. With these engines being fully electronic, they were able to make decent power relatively easy. They were produced from 2003 to 2007.
The current version of the Cummins is no longer a 5.9-liter. It has been bored and stroked to 6.7 liters. These engines incorporate a number of emissions equipment parts and represent the current evolution of the 160-horsepower engine that first appeared in late-1988. Now producing 385 horsepower and 850 lb-ft of torque, it is a powerhouse from the factory. If you are interested in the different versions or differences between years, click here for an in-depth article we did on the evolution of the engine.
But enough with the history lesson let’s talk power!
Jacob Bates’ 2001 12-Valve Cummins
While the head has been replaced and a factory injection pump was installed, the truck remains relatively the same as it was before. When Bates replaced the head, he sent it to Piers Diesel Research and had them add o-rings. The rest of the 24-valve Cummins is pretty much stock.

Bates was stationed in Hawaii for five years. He picked up this Hawaiian Ikaika Warrior Helmet while he was there. It symbolizes strength and power.
The VP44 fuel pump feeds a set of F1 Diesel Mach 7 injectors. To complete the combustion, the air is supplied by an Industrial Injection Silver 62 over a billet S475 low-pressure charger. The combination of turbos is able to produce 70 psi. When he wants to give it his all, Bates employs a water/methanol injection system and a single-stage Zex nitrous kit.
Controlling the delivery and timing of everything, Bates relies on an Edge Products Drag Competition tuner stacked with a Smarty. Behind the engine is a Goerend torque converter mounted to a 47RE automatic that was built by Gerald Kosub Transmission Services featuring a SunCoast valvebody.
All said and done, Bates rolled 601 hp with 1,198 lb-ft of torque on fuel only, and 727 hp with 1,472 lb-ft of torque on spray.
Kyle Peacock’s 1998 P-Pump/24-Valve Cummins
Under the hood of this ’98 is a 24-valve that has undergone some major work. While the pistons, rods, and crankshaft are stock, the factory camshaft was ditched in favor of a Hamilton Cams 181/210. A set of Manning Motorsports billet push rods were installed and the stock rockers have to overcome Hamilton 110-pound valve springs to open up the valves.
The engine was converted over to a P-pump that was built by CDS (Columbus Diesel Supply) and is a 12 mm 215 pump. The pump is fed by an Aeromotive A1000 fuel pump and feeds Industrial Injection 6x.016 injectors. The exhaust runs through a Steed Speed exhaust manifold and around the BorgWarner S400 turbine housing (0.91A/R). As the 75 mm compressor wheel sends air through the aFe POWER Bladerunner intercooler, which then directs the cooler air through the Bladerunner intake elbow and into the head. If Peacock so wishes, the cooled compressed air can meet with water/methanol thanks to a single-stage system.

Luck was with us today. If TSD didn’t notice the issue, we would have been picking up pieces of the truck off the ground.
Behind the flywheel is a triple disk Diesel Performance Converters converter which sends power through the fully-built Black’s Diesel Performance 47RE transmission. The rearend has been upgraded with Yukon axles. The power is then transmitted to the ground via the 20×12 Fuel Off-Road Octane wheels wrapped in 305/50R20 Nitto 420s.
Unfortunately, once Peacock got on the dyno, the guys at Truck Source Diesel noticed a vibration. After a quick inspection, they determined that the pinion was loose and it wasn’t safe to run the truck on the dyno. Peacock had TSD fix the truck and they re-dyno’d the truck a few days later. The truck ended up making multiple passes in the 760 range with a best run of 764 horsepower. Unfortunately, the tach pickup on the dyno failed and they didn’t get the torque on that specific run. Earlier, the truck made 764 hp and laid down 1,255 lb-ft of torque.
William Ellington’s 2007 Common Rail
To make that kind of power out of a third generation, Ellington started with a stock rotating assembly. In fact, the only part of the short block that has been upgraded is the camshaft. A Diesel Pro’s Killer B camshaft was installed a few years ago. At the same time, the push rods were upgraded to Smith Brothers and the valve springs were upgraded to F1 Diesel’s.
To make the power this Common Rail does, it all starts with an Engineered Diesel S400 turbo with a 69mm compressor wheel. The air is compressed up to 60 psi and is sent through the factory intercooler and into the head via a TSD intake elbow. When the piston is just about at TDC, fuel is injected through the F1 Diesel Flux 4.3 injectors which are fed by a duel PPE CP3 kit. The factory CP3 is an Industrial Injection 85-percent over pump and the top CP3 is a stock Duramax CP3. The timing and amount of fuel is handled by the custom tuning done by TSD. On fuel only, this truck makes 843 horsepower and 1,419 lb-ft of torque.
Ellington doesn’t use spray on the drag strip, just at the dyno. At this event, he did take advantage of the Nitrous Express dual-stage kit, which not only cools the air coming out of the turbocharger but also feeds the air running into the cylinder head. Holding the power and controlling it is done with a Goerend transmission.
Ellington runs a set of 20×10 MKW wheels up front and 20×12 in the rear. All are wrapped with Nitto’s 420s 305/50R20 tires. At the track, Ellington has run a best of 11.01 seconds in the quarter-mile at 120 mph, at 7,100 pounds still gets 17.6 mpg.
For his second run on the dyno, everything was working in unison and the truck laid down an impressive 1,036 hp and 1,759 lb-ft of torque.
Chance O’Daniel’s 2012 Ram 2500
O’Daniel’s truck is his daily driver that has been turned into a beast. The internals of the engine are stock, but air and fuel have been tweaked. It all starts with the custom set of compounds by Wicked Motorsports and Kustom Fabrications. The compounds start with an 84 mm BorgWarner S400 low-pressure charger feeding an S400 high-pressure with a 68 mm compressor wheel. Believe it or not, this large set of compounds lights very easily and O’Daniel is able to tow effectively with this combination.
With this much air, the stock intercooler was upgraded to a Mishimoto and the intake was upgraded to a Pusher.
For fuel, two stock CP3 pumps are mounted on the engine thanks to a dual CP3 kit from Industrial Injection, and the whole system is tuned by Done Right Diesel Performance.
Spinning with the flywheel is a Valair clutch held in place with a 3850 pressure plate. The rest of the running gear is stock. The truck is running on a set of Toyo Open Country 33×12.5R20 tires mounted on Fuel Octane wheels.
As we watched O’Daniel roll the dyno time and time again, we all could hear the truck limiting and defueling right around 2,600 rpm. Unfortunately, after a few different tunes and some tweaking, the issue wasn’t fixed and O’Daniel was only able to roll 806 horsepower. The best horsepower run he did have, the tach pickup lost its reading and we weren’t able to register a max torque on that run. In an earlier run, he was able to put down 1,370 lb-ft of torque. After this dyno day, O’Daniel put the truck back on the dyno for more tuning and the truck to date has made over 900 hp with the same modification but still has a lot left in it. Hopefully they will get it figured out and this will be a four-digit truck in the near future.
Ray Ross’ 2014 6.7-Liter Cummins
The last up was Ray Ross with his daily driver, a 2014 Ram 2500. The engine is relatively stock although the valve springs were upgraded to F1 Diesel’s and the stock intake horn was replaced with a BD Diesel Performance. The injectors were removed and the nozzles were replaced with 125 hp from Industrial Injection’s. The injectors are fed by an 85-percent over CP3 pump built by Industrial Injection.
Behind the Cummins is a South Bend 3250 dual disc clutch and stock transmission. The remainder of the driveline is stock, but the truck is rolling on a set of Ultra 22-inch wheels that are wrapped in 305/45R22 Toyo Proxes ST II.
Ross’ truck ended up being a last-minute fill in and he ended up staying up all night trying to get the truck ready for the day. We appreciate that, and he should be happy with the 751 horsepower he laid down with 1,393 lb-ft of torque.
We weren’t trying to pit any of these trucks against each other, instead, we tried to get a good sample of what is running the roads of Texas and the country. These are great examples of what each generation of Cummins is able to produce. Sure, there are a lot of trucks making less and even more power than these guys, but this is a good sampling.