In the world of diesel performance, it’s common to hear people claim the 7.3L was the best Powerstroke ever made and that 6.0L is nothing more than a boat anchor.
It didn’t take long after Ford released the 6.0L Powerstroke for massive problems to be uncovered. Even with the laundry list of problems, the 6.0L is still compared to the 7.3L. Let’s dive in and see which one is better.
As you may or may not know, Ford was essentially forced to kill off the 7.3L due to increasingly tough emissions standards. Being that the 7.3L started life in 1994, it wasn’t designed to work well with modern emissions systems such as an EGR.
The 6.0L was lower displacement and worked properly with modern emissions control systems, while still making more power than the 7.3L. Ford likely could’ve reused the overall architecture of the 7.3L but who knows how well that would work with emissions systems compared to the 6.0L.
Throughout the years of the 7.3L’s life, Ford uprated the engine five different times. Even with the minor changes over the years, it was still falling short in terms of power and efficiency compared to the competition such as the 6.6L Duramax.
There are a handful of things that made the 6.0L more efficient and more powerful, mainly the upgrade to 4 valve heads and a better injection system. Other features such as a way more advanced variable turbo helped the 6.0L ultimately make more power than the 7.3 right out of the box.
- 6.0 Production Run: 2003 – 2007 (for Super Duty applications)
7.3 Production Run: 1994.5 – 2003
- 6.0 Cylinder Head Material: Cast Iron
7.3 Cylinder Head Material: Cast Iron
- 6.0 Cylinder Block Material: Cast Iron
7.3 Cylinder Block Material: Cast Iron
- 6.0 Valvetrain: 4v
7.3 Valvetrain: 2v
- 6.0 Bore: 3.74 inches
7.3 Bore: 4.11 inches
- 6.0 Stroke: 4.13 inches
7.3 Stroke: 4.18 inches
- 6.0 C/R: 18:1
7.3 C/R: 17.5:1
- 6.0 Max HP: 325hp
7.3 Max HP 275hp
- 6.0 Max LB-FT: 570 lb-ft
7.3 Max LB-FT: 525 lb-ft
Due to the age of the 7.3L and what was readily available at the time, it was always stuck with a fixed geometry Garrett turbo. That’s not necessarily a bad thing.
A fixed geometry turbo can produce awesome results if it’s the right size for the power goals and the tuning is on point, but in the case of the 7.3L the fixed geometry turbo was somewhat laggy.
If you were to pick up a used truck with a 7.3L, chances are the turbo is old and in need of replacement anyone, but it’s just something to know.
The 6.0L on the other hand, was the first Powerstroke engine to receive a variable geometry turbocharger. This gave the 6.0L really good throttle response and tons of low-end torque while still maintaining good top-end power.
The VGT system works by giving the exhaust housing electronically controlled vanes which change the effective internal size of the exhaust housing.
Changing the size of the housing results in a change in exhaust gas velocity in the exhaust housing. To put it simply, at low RPM the housing decreases in effective size and at high RPM it expands and effectively becomes larger.
As you might have imagined, introducing an electronically controlled and hydraulically actuated system inside a turbocharger results in less-than-ideal reliability. While this system is very interesting and very effective, it’s known for failing significantly more often than a standard turbocharger.
With these engines being sold, modern turbocharger technology is far superior and you can find a much better turbo on the aftermarket.
In 1994, when the 7.3L was initially released, it featured a hydraulically activated, electronically controlled, unit injector fuel system. This came at a time when competitors such as the 12v Cummins were using mechanical injection systems.
The new and advanced injection system gave the 7.3L a leg up on the competition as far as power and emissions, at least until the competition also started to employ electronic injection systems.
The 7.3L uses a gear-driven pump on the front of the engine located near the lifter valley, and it’s known for being a very reliable system.
By the time the 6.0L came around, electronically injection systems were the norm. The 6.0L uses a similar injection system, but the pump is positioned at the back of the engine rather than the front and they’re super hard to access.
Accessibility wouldn’t be a problem if it was a reliable system, but unfortunately, it’s not. When the 6.0L oil pump fails, it’s a very big and expensive repair.
Being that oil is used to actuate the fuel injection event on an HEUI injector, the 7.3L injector body features an internal component called a poppet valve. This valve is what allows high-pressure oil to enter the injector and kickstart the chain of events that culminates in 21,000 psi worth of injection pressure leaving the injector nozzle.
The electronic solenoid up top is what gets energized (via the Injector Driver Module) when it’s time to fire. The poppet valve is one of the biggest wear items on 7.3L injectors, but they are known to last at least 200,000 miles.
The 6.0L fuel injector operates similarly to the 7.3L unit, but the valve that allows high-pressure oil to enter the injector body is referred to as a spool valve. Tighter tolerances, and a more technologically advanced injection system, allow the 6.0L Power Stroke to produce higher injection pressures and horsepower
Contaminants and dirty oil can wreak havoc on the spool valve, and it often doesn’t offer the same service life the poppet valve in the 7.3L injector does.
As you probably know, connecting rods are often the limiting factor in many engines. If you want big power, a built bottom end is needed for most engines. Unfortunately, there are a few things which hold the 7.3L back from making big power.
For 2001 to 2003 7.3L engines, you’ll find powdered metal connecting rods which are known to fail around 450 to 500whp. In the early 94 to 2000 engines, forged steel connecting rods were used and these are known for holding up to around 600whp. In the case of the 6.0L, you’re going to run into head gasket issues way before connecting rods becoming a limiting factor.
Thanks to the 6.0L being equipped with a bedplate and using an overall better design, it’s able to rev higher and withstand more power on stock internals.The stock connecting rods are good for as much as 750 to 800rwhp, and the valve train doesn’t have to be upgraded until you’re making serious horsepower and boost, compared the 7.3L where stiffer valve springs and stronger pushrods are essential when you start making big power.
It’s no secret the 6.0L has a laundry list of well-documented common problems. Of all those problems, EGR related issues seem to be the most common. Realistically, the simplest solution to this problem is to just delete the system with an EGR delete.
An EGR delete might not be legal depending on where you live and your truck may no longer pass emissions testing, so tread carefully when messing with EGR deletes. Other than deleting it, proper maintenance can keep the EGR system from clogging up.
7.3L Powerstroke Pros:
- 6 head bolts per cylinder.
- 300whp tuned.
- No emissions components.
- More reliable turbo.
- Good low end torque from displacement.
- Higher resale value.
- More reliable injection systems.
6.0L Powerstroke Pros:
- 325hp stock.
- 400whp tuned.
- Rev happy engine.
- More responsive variable turbo.
- Tough transmission.
- 800whp bottom end.
- Bed plate.
Out of all of this, there are a few key things to remember: the 6.0L makes more power with just a tune, it revs higher, it was a more responsive turbo, a bedplate, and a stronger bottom end, but it’s prone to head gasket issues, EGR failure, cracked heads, broken turbos, and injection system issues.
On the other hand, the 7.3L might not make as much power tuned, but it’s still plenty to push a truck around, it has a more reliable turbo, better resale value, and a more reliable injection system, but it has a weaker bottom end, a weaker automatic transmission, no bedplate, and in stock form it doesn’t much power.
Which one is better depends on what you’re going for and what matters most to you. If reliability is important, the 7.3L is the better engine, but if you want to make a ton of power without a built bottom end, the 6.0L is better. It should be noted all the 6.0L issues can be cured with a bulletproof kit.