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7.3 Powerstroke vs 5.9 Cummins Ultimate Guide

Chandler Stark

Meet Chandler

Chandler is an automotive expert that joined the DieselIQ and 8020 Media teams in 2022. He’s been working on and modifying cars from a young age and has a passion for JDM builds. However, Chandler is also a big fan of American muscle & diesel trucks. He delivers endless automotive knowledge and hands-on experience, and is a seasoned writer who spends some of his free time writing for The Grunge.

If you were looking for turbo-diesel power in the 1990s and early-2000s, you had two main choices: Ford’s 7.3 Powerstroke V8 or Dodge’s 5.9 Cummins I6. These were some of the first modern diesels to have direct injection and turbochargers as standard, opening up entire new worlds of performance opportunities. Though now long out of production, both the 7.3 Powerstroke and 12 and 24-valve 5.9 Cummins are the things of legend. Some consider them to be the best turbo-diesels of all-time still today. Read on to find out everything you need to know about the 7.3 Powerstroke vs 5.9 Cummins turbo-diesel engines. 

7.3 Powerstroke vs 5.9 Cummins: History

1989 Dodge Ram 2500 5.9 Cummins
1989 Dodge Ram 2500 with 12-valve 5.9 Cummins (Credit: Bring a Trailer/MelHPAS)

Of the 7.3 Powerstroke vs 5.9 Cummins, the Cummins came first. Beginning in 1984, Cummins began building the 5.9 inline-6 for use in agricultural equipment, where it excelled. Starting in 1989, Dodge began using a 12-valve version of the engine inside their ¾ and 1 ton full-sized pickups. The original 12-valve Cummins, or 6BT as it is often known, was revolutionary in terms of diesel engines. It had both direct injection and a turbocharger as standard, significantly boosting performance and reliability over previous diesels. 

After 10 years in production, Cummins brought out a new and improved version for 1998, the 24-valve 5.9 Cummins. As you can guess, the new Cummins had an extra exhaust and intake valve for each cylinder, greatly increasing performance. When the 12-valve Cummins was in production, it produced 160-215 horsepower and 400-440 lb-ft of torque, which were class leading at the time. The 24-valve Cummins jumped up to 235-325 horsepower and 460-610 lb-ft of torque. 

In 1994, Ford brought out their own turbo-diesel to compete with the Cummins: The Navistar built 7.3 Powerstroke V8. Like the Cummins, the new Powerstroke had direct injection and turbocharging as standard, giving Dodge its first real competitor. The Powerstroke was undoubtedly bigger, but that didn’t necessarily mean more powerful. While the Powerstroke’s 210-275 horsepower and 425-525 lb-ft of torque could best the 12-valve Cummins, they can’t compete with the most powerful 24-valves. 

Not only did the Powerstroke and Cummins turn out to be huge successes inside the F-series Fords and Ram series Dodges, they also helped reinvigorate the diesel market in America. Earlier experiences with diesels, like the dreaded Oldsmobile LF9 V8 from the 1980s, briefly made swore Americans off diesels, until the 12-valve came out a few years later in 1989.

The End of the Road

Both engines only lasted until the early-2000s, when Ford/Dodge phased them out due to emissions concerns. In their place was the 6.0 Powerstroke V8 and the 6.7 Cummins I6. Both the 7.3 Powerstroke vs 5.9 Cummins were the original DI turbo-diesels, and have a legendary reputation as such. Today, there are still countless 7.3 Powerstroke and 5.9 Cummins on the roads. They have proven to be extraordinarily reliable power plants that spawned the modern generation of turbo-diesels. 

Specs Comparison

Engine7.3 Powerstroke12-valve 5.9 Cummins24-valve 5.9 Cummins
Engine FamilyFord PowerstrokeCummins ISBCummins ISB
Engine ManufacturerNavistarCumminsCummins
Truck Model Years1994-1997, 1999-20031989-19981998-2007
Displacement7.3 liters (444 cid)5.9 liters (359 cid)5.9 liters (359 cid)
– 1994-1997 – Garrett TP38
– 1998-2003 Garrett GTP 38 (Wastegated)
– 1999-2003 – Garret GTP 38 (Wastegated & Intercooled)
– 1989-1991 – Holset H1C
– 1991-1993 – Holset H1C (Intercooled)
– 1994 – Holset WH1C (Intercooled)
– 1994-1998 – Holset HX35 (Intercooled)
– 1998-1999 – Holset HX35W (Intercooled)
– 2000-2004 – Holset HY35W Type D (Intercooled)
– 2004-2007 – Holset HE351CW (Intercooled)
Compression Ratio17.5:117.0:1Standard – 16.3:1High-Output – 17.2:1
Head/Block MaterialCast IronCast IronCast Iron
Bore & Stroke4.11 in x 4.18 in4.02 in x 4.72 in4.02 in x 4.72 in
Fuel SystemDirect Injection
– Hydraulic Electronic Unit Injection (HEUI)
– 98-140 cc injectors
Direct Injection
– 1989-1993 – Bosch VE44 Rotary
– 1994-1998 – Bosch P7100 Inline
Direct Injection
– 1998-2002 – Bosch VP44
– 2003-2007 – Bosch CP3
Valve TrainOverhead Valve (OHV)
16-valve (2 valve/cylinder)
Overhead Valve (OHV)
12-valve (2 valve/cylinder)
Overhead Valve (OHV)
24-valve (4 valve/cylinder)
Horsepower Output210-275 horsepower160-215 horsepower235-325 horsepower
Torque Output425-525 lb-ft of torque400-440 lb-ft of torque460-610 lb-ft

If you would rather consume this content via a video, check out our Ford 7.3 Powerstroke vs 5.9 Cummins video below:

5.9 Cummins Engine Design Basics

The 12-valve 5.9 Cummins debuted inside Dodge Ram trucks in 1989. It was a 5.9 liter (359 cid) inline-6, direct injection, turbocharged diesel engine. The valve train was a traditional overhead valve (OHV) design with a single in-block camshaft. The 12-valve Cummins had one exhaust valve and one intake valve per cylinder. 

The 12-valve block and cylinder head are both cast iron and are extremely strong. All versions have direct injection, but the pump changed over the years. Originally, Cummins used the Bosch VE44 rotary injection pump. This was an ultra-reliable unit that alleviated the need for glow plugs on cold starts like other diesels at the time. In 1994, Cummins switched to the Bosch P7100 inline injection pump, also known as the P-pump. The P-pump was again ultra-reliable and extremely high-flowing and lasted through 1998. 

For the turbo, the original was a Holset H1C non-intercooled unit from 1989–1991. Holset is owned by Cummins, and they manufacture the turbos themselves. In 1991, Cummins added an air-to-air intercooler. For 1994 only, some versions got the Holset WH1C turbo. However, most got the Holset HX35, which also had an intercooler and lasted through 1998. 

The 24-Valve Replaces the 12-Valve

Partway through the 1998 model year, Cummins replaced the 12-valve 5.9 with a new 24-valve version. The 24-valve Cummins added an exhaust and intake valve to each cylinder, helping with breathing and increasing performance. Valve-size stayed the same, but now the engine could work much more efficiently.

The majority of the engine stayed the same in terms of the block and internals, but Cummins again changed the fuel pump and turbo several times. From 1998-2002, Cummins used the Bosch VP44 rotary injection pump, which was extremely failure prone. This was a high-pressure fuel pump, and was implemented over stricter emissions standards. Unfortunately, it was garbage. In 2003, Cummins upgraded to the Bosch CP3, another very reliable pump that they still use today in the 5.9’s successor the 6.7 Cummins

For the turbo, from 1998–1999 Cummins continued to use the Holset HX35W, which they upgraded to the Type D from 2000–2004. From 2004–2007, Cummins used the Holset HE351CW. All versions used an air-to-air intercooler. In 2007, Cummins phased out the 5.9 Cummins for the larger and more powerful 6.7 Cummins

Engine Design Comparison

After seeing the success of the 6BT Cummins, Ford decided to get into the turbo-diesel game in 1994 with the release of the 7.3 Powerstroke. The Powerstroke is a 7.3 liter (444 cid), direct injected, V8, turbo-diesel engine. It uses a 12-valve OHV design with hydraulic lifters rather than solid like on the Cummins. Compression sits higher on the Powerstroke at 17.5:1, which is higher than even the HO Cummins. 

The block and cylinder heads are also durable cast iron like the Cummins’. Direct injection is also standard, using Ford’s “hydraulic electronic unit injection” (HEUI) system. The HEUI system used dual-oil pumps, a low pressure and high pressure pump, which reached up to 3,000 PSI. At first, injectors were just 98 cc, but soon jumped. In non-CARB engines, they eventually released 140 cc in standard or 160 cc in HO models. CARB models were limited to 130 cc injectors due to emissions. 

For the turbo, from 1994–1997 Ford used a Garrett TP38 turbo. In 1998, this became the GTP 38 when they added a wastegate. Starting in 1999, Ford added an air-to-air intercooler for improved performance and efficiency. 

7.3 Powerstroke vs 5.9 Cummins Reliability

7.3 PowerStroke turbo-diesel

In terms of reliability, both the 7.3 Powerstroke and 5.9 Cummins are rated in the extremely dependable category. They are both known to exceed 350,000 miles without issue, and the 12-valve Cummins can blast through 500,000 miles when properly maintained — even when modified. It’s truly incredible how stout and sturdy these engines really are, especially considering they are relying on 1980s and 1990s Dodge/Ford engineering. 

Many people consider the 12-valve Cummins to be the most reliable and well built diesel engine ever made. Even when compared to the newer 6.7 Cummins, the 12-valve stands out for its exceptional reliability. 

Really, the only flaw with the engine is what’s known as the “killer dowel pin” (KDP). The KDP is the literal achilles heel of the engine, and occurs when the front-aligned dowel pin falls into the cam gear. This causes catastrophic engine damage 95% of the time and happens due to wear from repeated heat-cycling. Luckily, a fix for the KDP is pretty easy and cheap, making it the engine basically bulletproof afterwards. 

For the 24-valve Cummins, by far the biggest issue are the Bosch VP44 high-pressure fuel pump, the lift pump, and the fuel injectors. All of these are prone to failure or leaking, making the 1998–2002 24-valves the least desirable engines of the bunch. Luckily, this is not a problem for 2003+ 24-valves with the CP3. 

Performance Comparison

While the power figures for these engines might seem pretty pedestrian by today’s turbo-diesel standards, for the time they were quite powerful. The earliest engine, the 12-valve Cummins, ranged from 160-215 horsepower and 400-440 lb-ft of torque. At the time, the massive torque figure was mind-blowing, and easily made the Cummins one of the hottest engines on the market. At first it only made 160 horsepower, and didn’t even crack 200 until 1996. 

When the 24-valve came out in 1998, it took Cummins a few years to realize the full benefits of the extra valves. Starting in 2003, the Cummins broke 300 horsepower for the first time, just two years after breaching 500 lb-ft of torque. A high-output version was available from 2001–2004, and upped performance over the standard Cummins by a solid amount. From 2005–2007, the 24-valve Cummins produced an incredible 610 lb-ft of torque, by far the best in class. 

Ford’s 7.3 Powerstroke could keep up with the 12-valve, but not quite with the 24-valve. Initially, the Powerstroke produced 210 horsepower and 425 lb-ft of torque. That jumped to 235 horsepower and 500 lb-ft in 1998, and finally to 275 horsepower and 525 lb-ft from 2000-on. The Powerstroke never reached the heights of the 5.9 Cummins’ power, but was still plenty capable of hauling and towing. 

Performance Upgrades & Tunability

AirDog lift pump for 12v 5.9 Cummins
Credit: AirDog

Both the 7.3 Powerstroke and 5.9 Cummins are great stock, but they have also been enormously popular on the aftermarket. As a result, it’s pretty rare to find a completely stock Powerstroke or Cummins at this point. However, due to both engines’ incredible durability, they have been shown to hold up very well when modded. And they can make a ton of power. 

The 5.9 Cummins however takes the cake from a performance potential/tunability standpoint. The earlier model 7.3’s up through 2001 can handle some solid power but the 2002+ versions switched to powdered metal internals which hampered power limits. Additionally, the HEUI injection system is a big performance limitation as well.

Ultimately, Which is Better?

So which is truly better, the 7.3 Powerstroke vs 5.9 Cummins? Well, that’s pretty much an impossible question to answer. Both the 12-valve Cummins and 7.3 Powerstroke are regarded by many as the best respective members of their engine families. Even among all turbo-diesels in general, the 5.9 Cummins and original Powerstroke are often at the top of the historical rankings.

They have proven to be virtually indestructible if they are well maintained, and they can make obscene amounts of performance. We here at DieselIQ prefer the 12-valve 5.9 Cummins, but all of them are exceptional choices. 


Which is better, a Cummins or Powerstroke?

Both the 12-valve Cummins and 7.3 Powerstroke are regarded by many as the best respective members of their engine families. Even among all turbo-diesels in general, the 5.9 Cummins and original Powerstroke are often at the top of the historical rankings. They have proven to be virtually indestructible if they are well maintained, and they can make obscene amounts of performance.

Which came first, the Powerstroke or Cummins turbo-diesels?

The 12-valve Cummins was the first of the modern turbo-diesels to hit the market in 1989 in Dodge Rams. That was followed by the 7.3 Powerstroke in 1994, and the 24-valve Cummins in 1998.

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