If you’ve spent any time around diesel enthusiasts lately, you’ve probably noticed a trend:
More and more 6.7 Cummins owners are doing 2nd Gen swaps.
From daily-driven street trucks to full-blown competition builds, the 2nd Gen swap has become one of the most popular mods in the Cummins world.
So what exactly is a 2nd Gen swap? Why do people do it? And is it right for your truck?
Let's talk about it.
What Is a 2nd Gen Swap?
A “2nd Gen swap” refers to converting a 2003+ Cummins engine (most commonly a 6.7L) to use a 2nd generation-style exhaust manifold and turbocharger location similar to the 1994–2002 Cummins trucks.
Instead of the factory-style turbo location, the turbo sits higher and more forward, with a simple, open layout that accepts a wide range of aftermarket turbochargers.
The 2nd Gen-style manifold is a divided manifold; which provides more equalized drive pressure, balanced EGTs, and a wider range of turbo options.
Most 2nd Gen swaps involve:
- 2nd Gen style exhaust manifold
- S300 or S400 frame turbocharger
- Custom downpipe and intake piping
- Oil feed and drain lines
Why Diesel Owners Love 2nd Gen Swaps
The popularity isn’t random. 2nd Gen swaps offer some real advantages.
Simplicity
The layout is straightforward and easy to work on. No crowded VGT housing. No complex actuator. No tight factory packaging.
Turbocharger Freedom
Owners can choose from an enormous range of:
- S300 single turbos
- S400 single turbos
This allows builds to be tailored for towing, street performance, or all-out horsepower.
Big Power Potential
2nd Gen swaps support very large turbochargers and compound setups, making them ideal for high-horsepower builds.
Cost Efficiency
Compared to compounds and high-end VGT turbos, many 2nd Gen turbo options offer excellent performance per dollar.
Performance Benefits
When paired with proper supporting mods, a 2nd Gen swap can deliver:
- Improved airflow
- Lower exhaust backpressure
- Lower exhaust gas temperatures
- Improved driving experience (depending on turbo choice)
- Higher horsepower ceiling
- Better turbo/exhaust sound (bonus benefit)
That’s why they’re so common on trucks chasing serious numbers.
The Downsides of a 2nd Gen Swap
No mod is perfect. There are tradeoffs.
Loss of VGT Features
Most 2nd Gen swaps replace the factory VGT turbo, meaning you lose:
- Factory exhaust brake
- Some low-RPM responsiveness
More Supporting Mods Required
A 2nd Gen swap often leads to a domino effect. To take full advantage of an S300 or S400 turbo, Cummins owners often wind up spending thousands of additional dollars on:
- Tuning revisions
- Larger injectors
- Larger CP3 pump(s)
- Built transmission
- Head studs
- Push rods
- Valve springs
- And more!
Not Emissions-Friendly
2nd Gen swaps are generally considered off-road or race-use setups and will not be emissions compliant.
Please Note: Due to their incompatibility with federally-required emissions components, we don't offer 2nd Gen Swap Kits for the 6.7 Cummins here at FASS Motorsports.
Install Complexity
While straightforward for experienced builders, it’s more complex than a simple bolt-on turbo.
Who Should Consider a 2nd Gen Swap?
2nd Gen swaps make the most sense for owners who:
- Want big power potential
- Plan future turbo upgrades
- Are building a performance-focused truck
- Understand the tradeoffs
They are often overkill for basic daily drivers or mild towing trucks.
How FASS Motorsports Supports 2nd Gen Swap Builds
While we do not currently sell complete 2nd Gen swap kits, we absolutely support these builds with the critical components that make them successful.
At FASS Motorsports, we can supply:
- Turbochargers
- Oil feed and drain lines
- Fittings and hardware
- FASS Fuel Systems
- Larger injectors
- Larger CP3 pumps
- Head studs
- Valve covers
- And more supporting parts
We’re happy to help you piece together a combination that matches your budget and horsepower goals.
Fuel System Is Critical
Big airflow means nothing without proper fueling.
That’s why most serious 2nd Gen swap builds run a FASS Fuel System to ensure:
- Clean fuel
- Proper pressure
- Air and vapor separation
- Injector and pump protection
A strong fuel foundation keeps expensive parts alive.
Final Thoughts
2nd Gen swaps are popular for a reason. They offer simplicity, flexibility, and massive performance potential.
But they aren’t magic — and they aren’t for everyone.
If your goal is a high-performance 6.7 Cummins build, a 2nd Gen swap may be exactly what you’re looking for.
Have Questions? We're here to help.
- Phone: (636) 429-7020
- Email: info@fassmotorsports.com
FASS Motorsports
25 Town and Country Dr.
Washington, MO 63090
