If you’re driving a 2019 1500 GMC Sierra AT4 with the 6.2L V8, chances are you already appreciate raw power. But if you’re looking to unlock more horsepower, torque, and throttle response, you need to consider one key upgrade—long tube headers. These performance exhaust components can dramatically improve engine breathing, boost efficiency, and amplify your Sierra’s sound.
In this detailed guide, we’ll explore everything about long tube headers for 2019 1500 GMC Sierra AT4 6.2—from how they work and why they matter to choosing the best brands, tuning tips, and real-world benefits. Whether you’re building a street beast or prepping for the track, this upgrade could be your game-changer.
What Are Long Tube Headers and Why Do They Matter?
Understanding the Performance Advantage
Long tube headers are exhaust manifolds that replace the factory cast iron manifolds on your truck. Unlike shorty headers, long tube headers feature extended primary tubes, which allow exhaust gases to exit the cylinders with less restriction. This design helps improve scavenging, reduce backpressure, and increase power at mid to high RPMs.
For the 2019 GMC Sierra AT4 6.2L, this modification enhances overall performance. Since the stock exhaust system is built for quiet operation and emissions compliance, it’s restrictive. Replacing it with long tube headers lets the engine breathe, which translates into better combustion and more horsepower.
You’re not just making it louder—you’re unlocking hidden potential.
Why Choose Long Tube Headers for the 2019 1500 GMC Sierra AT4 6.2?
Tailored Performance for a Powerful Truck
The 2019 GMC Sierra AT4 is already loaded with off-road features, aggressive styling, and a brawny 6.2-liter V8. But stock performance always leaves room for improvement. Long tube headers enhance what GM started, pushing your AT4’s 420 horsepower even further.
Here’s what you’ll gain by upgrading:
- Horsepower Gains: Expect up to 20–35 additional HP with proper tuning.
- Improved Throttle Response: Acceleration feels quicker and more immediate.
- Deeper, Aggressive Exhaust Note: Your Sierra sounds like a real performance truck.
- Increased Torque: Especially useful for towing, hauling, or off-road climbs.
These improvements create a more thrilling and responsive driving experience—on pavement and beyond.
Materials Matter: What Long Tube Headers Are Made From
Choose the Right Material for Durability and Performance
Not all long tube headers for 2019 1500 GMC Sierra AT4 6.2 are created equal. One of the first choices you’ll make is material. The most common options include:
- Stainless Steel: Corrosion-resistant, strong, and long-lasting. Ideal for daily driving and all-weather conditions.
- Mild Steel: Budget-friendly but prone to rust without ceramic coating.
- Ceramic Coated: Helps manage heat, protecting nearby components and improving exhaust flow.
For most Sierra AT4 owners, stainless steel headers strike the best balance between durability, heat resistance, and appearance. They’re built to last, even under demanding conditions.
Best Brands for Long Tube Headers for 2019 GMC Sierra AT4 6.2
Proven Performance You Can Trust
With so many aftermarket options, choosing the right brand is critical. These manufacturers have a reputation for quality, fitment, and real-world performance:
1. Kooks Headers and Exhaust
- CNC mandrel-bent stainless steel
- Excellent craftsmanship
- Compatible with performance cats or off-road pipes
2. Texas Speed & Performance (TSP)
- Affordable and high-quality
- Popular in GM performance circles
- Great for pairing with a custom camshaft setup
3. American Racing Headers (ARH)
- Known for perfect fitment
- Made in the USA
- High flow and race-ready
4. Stainless Works
- Aggressive tone and superior TIG welding
- Bolt-on compatibility for many GM applications
These brands deliver performance, sound, and reliability—exactly what your Sierra AT4 demands.
Installation Overview: What to Expect
DIY or Professional? Know Before You Wrench
Installing long tube headers on a 2019 GMC Sierra AT4 6.2 isn’t exactly beginner-level. It requires mechanical skill, the right tools, and ideally, a lift. Here’s what’s involved:
- Removing the factory manifolds and catalytic converters
- Installing the new long tube headers
- Replacing or modifying the Y-pipe (sometimes included with kits)
- Retuning the ECU to eliminate CELs and optimize performance
If you’re mechanically inclined and have access to a garage setup, it’s a doable weekend project. Otherwise, professional installation is recommended for a seamless fit and proper tuning.
Tuning Is a Must After Installation
Unlock Full Power and Avoid Check Engine Lights
After installing long tube headers, tuning your ECU is critical. The factory computer is designed to work with restrictive manifolds and catalytic converters. Long tube headers alter airflow dynamics and often relocate O2 sensors.
Without a tune, your engine might run lean, and you’ll likely trigger a Check Engine Light (CEL). Tuning solves this while maximizing the performance benefits. You’ll see:
- Better throttle response
- More horsepower and torque
- Improved fuel efficiency (in some cases)
- Eliminated CELs
Popular tuners like HP Tuners or DiabloSport work well with GM vehicles. Many header manufacturers even offer mail-order tunes tailored to your setup.
Performance Gains: What You Can Expect
Real Results on the Dyno and the Road
So, how much performance can you really gain with long tube headers for your 2019 GMC Sierra AT4 6.2? While results vary depending on supporting mods and tuning, most drivers report:
- Horsepower gains between 20 and 40 HP
- Torque increases up to 30 lb-ft
- Noticeably stronger midrange power
When combined with a cold air intake, performance exhaust, and tuning, your Sierra can gain over 60 HP at the crank—all while sounding incredible. That means more pull when towing, faster launches, and an overall more engaging drive.
Legal Considerations: Street vs. Off-Road Use
Know Your State’s Emissions Laws
Long tube headers often remove or relocate catalytic converters, which can violate emissions laws in certain states. If you plan to drive your 2019 GMC Sierra AT4 6.2 on public roads, check your local regulations.
- California and New York: CARB compliance is mandatory. Most long tube headers are not street-legal here.
- Texas, Florida, and others: More lenient, but still require cats for daily drivers.
- Off-road or track-only builds: No restrictions apply.
Always choose headers with high-flow cats if emissions testing is required in your area. Better yet, select a 50-state legal system if you want peace of mind and daily drivability.
Sound Comparison: OEM vs. Long Tube Headers
Hear the Difference
One of the most immediate benefits you’ll notice after installing long tube headers on your 2019 Sierra AT4 6.2 is the exhaust note. The deep rumble and aggressive tone are unmistakable. Here’s how it compares:
- Stock System: Quiet, subdued, refined
- Long Tube Headers + Stock Muffler: Louder idle, deeper tone under load
- Long Tube Headers + Aftermarket Exhaust: Throaty growl, aggressive bark at wide-open throttle
Many owners find this sound addictive. It matches the power under the hood and transforms your Sierra into a true performance truck.
Supporting Mods to Maximize Gains
Build a Balanced Performance Package
While long tube headers offer significant performance gains, combining them with other mods unlocks your Sierra’s full potential. Here’s what to pair them with:
- Cold Air Intake: Helps feed the engine cooler, denser air
- Cat-Back Exhaust: Complements header flow for better sound and performance
- Performance Camshaft: When tuned properly, adds major top-end power
- Ported Throttle Body: Improves throttle response and airflow
These upgrades work together to create a cohesive system, pushing your 6.2L V8 past factory limits and into serious performance territory.
Common Myths About Long Tube Headers
Separating Fact from Fiction
Before investing in long tube headers for your 2019 GMC Sierra AT4 6.2, let’s clear up a few misconceptions:
- Myth: Headers always trigger CELs.
Fact: Tuning resolves this issue entirely. - Myth: Headers ruin low-end torque.
Fact: Long tubes actually enhance midrange and top-end without hurting low-end on tuned setups. - Myth: Headers kill fuel economy.
Fact: With proper tuning, your MPG may stay the same or even improve under cruising conditions. - Myth: They make your truck too loud.
Fact: Exhaust volume depends on your muffler and exhaust system, not just the headers.
Understanding these truths will help you make a confident upgrade decision.
FAQs About Long Tube Headers for 2019 1500 GMC Sierra AT4 6.2
Do long tube headers void my factory warranty?
Yes and no. If the headers cause a failure (like a broken sensor), that component may not be covered. But unrelated systems—like suspension—remain protected under federal law.
Can I install long tube headers without tuning?
Technically yes, but it’s highly discouraged. You’ll likely trigger a Check Engine Light and won’t gain full performance benefits without a tune.
Are long tube headers street-legal?
Not always. If your setup deletes or relocates catalytic converters, it may not be legal in emissions-restricted states. Check your local laws.
What’s the typical cost of parts and installation?
Parts range from $700 to $1,500 depending on brand and features. Installation can cost $500–$1,000, especially if tuning is included.
Will I hear a noticeable sound difference?
Absolutely. Long tube headers significantly deepen and enrich the exhaust tone, even with the stock muffler.
Conclusion: Transform Your 2019 GMC Sierra AT4 6.2 with Long Tube Headers
Upgrading to long tube headers on your 2019 GMC Sierra AT4 6.2 is one of the most impactful changes you can make. You’ll gain horsepower, torque, throttle response, and an aggressive exhaust note that matches the truck’s performance image.
Whether you’re conquering trails, dominating the street, or building a weekend warrior, this upgrade delivers real-world results. With the right brand, a solid tune, and supporting mods, your Sierra won’t just sound mean—it’ll run like a beast.
