The Ultimate Guide to Scat Pack Mods: What Works and What Doesn’t

At Dusterhoff Racing, we spent six months rigorously testing bolt-on modifications for the 6.4L HEMI Scat Pack, leaving no stone unturned in our pursuit of real, repeatable gains. Our approach was comprehensive—we didn’t just throw parts on and take a single dyno pull. Instead, we tested each modification back-to-back, logging five repeated dyno runs per test to eliminate anomalies and ensure accuracy. We ran each setup both with and without tuning to measure the raw mechanical gains versus the optimized potential. And we didn’t stop there—we tested various combinations of modifications to see how they interacted, whether they stacked effectively or hit diminishing returns.

From cold air intakes to throttle bodies, headers, and mid-pipes, we ran them all through the wringer. Some upgrades delivered exactly as promised, while others… well, let’s just say marketing hype doesn’t always match real-world results. We dialed in air/fuel ratios, tweaked ignition timing, and optimized shift points to see just how much more power we could squeeze out. The results? Some mods proved to be absolute game-changers, offering significant horsepower and torque increases, while others barely moved the needle.

Through it all, we gathered the data, sorted the facts from fiction, and came away with a clear picture of what works best for unlocking power on the 6.4L HEMI. Stay tuned as we break down our findings—what’s worth your hard-earned cash, what’s overrated, and how to maximize the performance of your Scat Pack.

Cold Air Intake: Stock vs. Aftermarket

We tested every cold air intake on the market, from budget-friendly options to premium high-flow designs, to see how they stacked up against one of the most common DIY upgrades—the Hellcat lower airbox. The Hellcat box is a go-to for Scat Pack owners looking for a cost-effective way to improve airflow, but we wanted to know if any aftermarket intakes could consistently outperform it.

After running each intake through multiple dyno sessions, both with and without tuning, the results were clear: most aftermarket intakes offered no measurable advantage over the Hellcat lower airbox. Some even performed worse, either due to heat soak, poor airflow dynamics, or ineffective filter placement.

The one exception? The JLT Cold Air Intake. Unlike the others, the JLT consistently delivered measurable performance gains, showing an average increase of 7 wheel horsepower over the Hellcat box. This wasn’t just a one-off result—we saw repeatable improvements across multiple tests, confirming that its design truly enhances airflow and engine efficiency.

For those chasing every last bit of power, the JLT intake proves to be a worthwhile investment. It provides a noticeable bump in performance without the guesswork, making it the best option for Scat Pack owners who want to squeeze out more power beyond the Hellcat box upgrade.

Upgraded Intake Manifold

Many enthusiasts turn to intake manifolds as a way to unlock additional power, but not all upgrades are created equal. We put this to the test by evaluating two ported 6.4L manifolds from well-known companies, along with the Holley Sniper and Edelbrock intakes, to see how they performed on a stock 6.4L HEMI. The results? On a completely stock engine, none of these manifolds produced measurable gains.

However, when paired with a camshaft upgrade, the Holley Sniper intake stood out in a big way, picking up 45 wheel horsepower. This reinforced what we already suspected—while the factory intake is designed for a balance of drivability and performance, an aftermarket manifold can significantly improve airflow, throttle response, and overall power output, especially in the mid-to-high RPM range where a cammed engine thrives.

For those looking to take their 6.4L HEMI to the next level, a high-performance intake manifold is a must-have mod. Not only does it enhance power by allowing more air to reach the combustion chamber, but many aftermarket options also offer better heat resistance, durability, and optimized runner lengths to improve efficiency.

Our top recommendation? The Gen III HEMI Intake from BluePrint Engines, as Holley no longer produces their Sniper Intake for the Gen II Hemi. This fabricated sheet metal intake is the ultimate bolt-on upgrade, designed to fit right the first time—no injector spacers, no awkward oil neck placement, and a properly positioned PCV port for a clean, hassle-free installation.

Beyond convenience, this intake is built for serious power. By improving airflow and velocity, it helps your HEMI breathe deeper and pull harder across the rev range. Whether you’re building, swapping, or just upgrading, the BluePrint intake delivers the best combination of affordability, quality, and performance. And because we believe in making your life easier, we even include throttle body bolts—because details matter.

Longtube Headers and Exhaust

Longtube headers are a staple mod for HEMI performance, and while our testing showed a modest 5-wheel horsepower gain on a stock 6.4L Scat Pack, their real benefits go beyond peak numbers. By improving exhaust flow and reducing backpressure, longtube headers unlock 20-30+ HP with proper tuning, especially in the mid-to-high RPM range. The deep, aggressive exhaust note they produce is another major perk, giving your HEMI the sound it deserves.

Beyond power and sound, longtube headers also enhance throttle response and engine efficiency, allowing for smoother combustion and even potential fuel economy gains under normal driving. To maximize performance, a tune is highly recommended—it optimizes the air/fuel ratio and prevents check engine lights from factory catalytic converter removal.

If you’re planning bigger mods like a camshaft or supercharger, longtube headers are a must-have to prevent airflow bottlenecks and ensure your engine breathes freely. Whether you’re chasing more power or just want a more thrilling driving experience, upgrading to longtube headers and a high-flow exhaust system is one of the best bolt-on mods for your 6.4L HEMI.

Our recommended Headers:

Our recommended exhaust system:

Custom Grind Camshaft Kit: The Game Changer

Upgrading the camshaft in a 6.4L HEMI Scat Pack engine is one of the best ways to unlock significant horsepower and torque gains, especially in the mid-to-high RPM range. Here’s why a performance cam upgrade is a game-changer:

A custom camshaft upgrade is one of the most effective mods for Scat Pack owners looking for serious power. In our testing, a properly tuned setup delivered 40-45 wheel horsepower, with potential gains of 50-100+ HP when paired with supporting mods like long tube headers, a ported intake, and a high-flow exhaust.

By increasing valve lift and duration, a performance camshaft allows more air and fuel into the combustion chamber, improving combustion efficiency, mid-range torque, and high-RPM power. The result? A stronger, more aggressive powerband that pulls harder across the rev range. Whether you’re after better street performance, track dominance, or a choppy idle that turns heads, a cam swap is a game-changer for naturally aspirated and boosted builds alike.

Beyond horsepower, a performance cam sharpens throttle response and expands the RPM range, unlocking the 6.4L HEMI’s full potential. The stock cam is built for emissions and fuel efficiency, limiting performance—swapping it out lets your engine breathe better and rev higher, delivering quicker acceleration and more top-end power.

And let’s talk sound—a bigger cam gives your HEMI that unmistakable lope at idle, making it sound as mean as it performs. The more aggressive the cam profile, the deeper and rowdier the exhaust note, setting your Scat Pack apart from the rest.

A cam swap also amplifies the benefits of other mods, making intakes, headers, and tuning even more effective. Whether you’re building for the street, strip, or road course, there’s a cam profile tailored to your goals. And if you’re planning for forced induction, a boost-friendly cam ensures efficient airflow and maximum power gains without overloading the valvetrain.

If you’re serious about unlocking the full potential of your 6.4L HEMI, a custom camshaft upgrade should be at the top of your list.

Considerations

Tuning is required to optimize fuel, timing, and idle stability.
Valve springs & pushrods often need upgrading to handle the extra lift and RPM, these are included in all of our Cam Kits.
Driveability depends on the cam profile—bigger cams may affect low-speed manners. This can be addressed with an upgraded Converter, we recommend Converters from Sipple Performance.

Our options:

An upgraded camshaft is one of the best ways to wake up your 6.4L HEMI, delivering huge power gains, a nastier exhaust note, and improved throttle response. Whether you’re going all-out for track performance or just want more grunt on the street, a cam swap is a must-have mod for serious HEMI performance.

Check out this page for more info on all of our Camshafts and Cam Kits!

E85 Conversion: Is It Worth It?

Switching to E85 fuel provided a modest 5-wheel horsepower increase on average in our testing. While that number might not seem impressive on its own, the real power of E85 lies in its higher octane rating and cooling properties, which allow for more aggressive ignition timing and increased boost levels in forced induction applications.

E85 has a higher ethanol content (typically around 85%, depending on local blends), which gives it superior knock resistance compared to pump gas. This means the engine can safely run more advanced timing, unlocking greater horsepower and torque gains—especially when paired with a performance tune. The cooling effect of ethanol also helps lower intake air and combustion temperatures, reducing the risk of detonation and allowing the engine to run more efficiently under high loads.

For naturally aspirated setups, the immediate horsepower bump may be small, but the ability to run a more aggressive tune makes E85 an attractive option. On boosted applications, where knock resistance is even more critical, the benefits become even more pronounced—allowing for higher boost pressures, safer power gains, and improved overall reliability.

The trade-offs? Increased fuel consumption—E85 burns faster than regular gasoline due to its lower energy density, so expect to see a drop in fuel economy. However, for those chasing maximum performance from their 6.4L HEMI, the ability to push the engine harder and safer makes E85 a worthy upgrade.

The 605 Package: The Ultimate NA Setup

If you’re looking for the most potent naturally aspirated (NA) setup for your 6.4L HEMI Scat Pack, look no further than The 605 Package—a carefully selected combination of proven performance upgrades that work together to maximize horsepower, throttle response, and overall drivability. This package is designed for those who want to push the limits of their NA setup while keeping their engine reliable and responsive.

What’s Included in the 605 Package?

✅ Custom Camshaft Upgrade – The heart of the build, this camshaft is designed to unlock 40-50+ wheel horsepower, improve mid-to-high RPM power, and give your HEMI that aggressive lopey idle that turns heads.

✅ JLT Cold Air Intake – The best performing cold air intake in our testing, delivering 7-wheel horsepower gains over the stock Hellcat lower airbox while improving airflow for even bigger power gains with supporting mods.

✅ Blueprint Intake Manifold – This high-flow intake is engineered for maximum airflow and efficiency, helping to extend the powerband and complement the camshaft’s increased valve duration. No messy fitment issues—just bolt it on and go.

✅ Longtube Headers – Enhances exhaust scavenging, improves flow, and unlocks the true sound and power potential of the 6.4L HEMI. Gains of 20-30 HP are common when paired with proper tuning.

✅ Custom Performance Tune – Ties it all together, ensuring the air/fuel ratio, ignition timing, and throttle response are dialed in perfectly for maximum power and reliability. Expect sharper acceleration, increased torque, and a completely transformed driving experience.

What Can You Expect?

When combined, these mods work in harmony to push the 6.4L HEMI to the next level. With proper tuning, The 605 Package delivers around 600-610 crank horsepower—a gain of about 80-85 wheel horsepower- a massive improvement over stock while maintaining excellent drivability. You’ll experience:

🔥 Stronger mid-range & top-end power
🔥 Crisper throttle response
🔥 A more aggressive exhaust note & idle
🔥 Improved airflow & efficiency
🔥 Increased power potential for future mods

If you want the ultimate NA setup that maximizes every ounce of performance from your Scat Pack’s 6.4L HEMI, The 605 Package is your answer. Big power, no boost required.

Rear Suspension Upgrades

Upgrading the rear suspension on a Dodge Scat Pack—especially with the AAD Drag Pack—is a must-have for eliminating wheel hop, improving traction, and maximizing power transfer. The stock suspension is built for comfort, but under hard launches or big power, it struggles with instability, excessive flex, and inconsistent grip. The AAD Drag Pack’s upgraded control arms, toe links, and adjustable components stabilize the rear suspension, reducing wheel hop—a major cause of broken axles and lost traction.

By keeping the tires planted, this upgrade results in quicker 60-foot times, improved stability, and better high-speed control. For drag racing, it helps maintain consistent launches with minimal tire spin, while for street and road course driving, it sharpens handling and reduces body roll. If you’re running stickier tires, high horsepower, or forced induction, the factory suspension becomes a weak point, making reinforced components essential for reliability and performance.

The adjustable nature of the AAD Drag Pack allows you to fine-tune suspension geometry for optimal weight transfer and traction, whether you’re at the strip, on the street, or hitting corners on a road course. Paired with BMR’s Rear Cradle Lockout Kit and performance shocks, it eliminates unwanted flex, keeps alignment in check, and delivers the grip you need. If you’re serious about putting power to the pavement and getting the most out of your HEMI, this upgrade is one of the best investments you can make.

Final Thoughts

A rear suspension upgrade, especially with the AAD Drag Pack, BMR Rear Cradle Lockout Kit, and supporting mods, is essential for putting power to the pavement, improving stability, and keeping your Scat Pack performing at its best. If you’re tired of wheel hop, inconsistent launches, or losing traction, it’s time to dial in your suspension and get the most out of your HEMI!

Differential Upgrades and Bracing

Upgrading the differential and adding a differential brace to your Dodge Scat Pack is essential for improving durability, traction, and power delivery, especially under high-torque conditions like hard launches or high-horsepower builds. The factory ZF rear differential works fine for stock power, but it struggles under aggressive driving and modifications such as superchargers or drag racing. The DIRS Differential Brace reinforces the differential housing, preventing flex and maintaining structural integrity under stress. This reduces the risk of differential case cracks, gear slippage, or complete failure, ensuring that your drivetrain remains reliable and efficient during hard acceleration.

Upgrading to a Wavetrac Limited-Slip Differential (LSD) is another game-changer for traction and performance. Unlike the stock differential, which can result in the dreaded “one-wheel peel,” the Wavetrac LSD keeps both rear wheels engaged, ensuring more consistent power transfer. This design is highly effective in low-traction conditions like wet roads, gravel, or drag strips, dramatically improving acceleration, cornering stability, and overall traction. Whether you’re launching hard or cornering at high speeds, this LSD offers superior power delivery and enhanced control, making it easier to keep your Scat Pack stable and predictable.

The combination of a stronger LSD and the DIRS Differential Brace also helps eliminate wheel hop and reduce drivetrain shock, which are common issues during hard launches or aggressive acceleration. Wheel hop can put excessive strain on components like axles and the differential, leading to potential damage. By ensuring both wheels maintain traction and reinforcing the differential housing, these upgrades stabilize the rear end and improve overall handling. This is crucial for anyone running a high-performance setup, as it minimizes the risk of catastrophic drivetrain failures while improving traction and reducing unwanted flex.

For those with high-horsepower builds, drag radials, or forced induction, these upgrades are indispensable. The stock differential isn’t designed to handle significant power and repeated abuse. A stronger aftermarket LSD ensures your drivetrain can keep up with your engine modifications, distributing power more evenly during acceleration, cornering, and high-speed driving. This creates a more predictable and controlled driving experience, whether you’re at the track or enjoying spirited street driving. In short, these differential upgrades support big power builds, enhance vehicle stability, and ensure your Scat Pack performs reliably under even the most demanding conditions.

Final Thoughts and Recommended Parts:

If you’re pushing your Scat Pack hard—whether at the track, strip, or just on the street—a Wavetrac LSD upgrade and a DIRS Differential Brace are essential when making big power. These upgrades prevent costly failures, improve traction and handling, and ensure every bit of power gets to the pavement where it belongs.

Supercharger Kits

Adding a supercharger to a 6.4L HEMI transforms your Scat Pack into a powerhouse, offering massive horsepower and torque gains. With a properly installed and tuned supercharger, you can add 150 to 300+ horsepower, pushing your Scat Pack into Hellcat-level performance. This results in neck-snapping acceleration and instant torque that enhances every driving experience.

A supercharger delivers immediate, on-demand boost, offering improved low-end torque and throttle response for quicker launches and stronger mid-range power. It provides smooth, consistent power throughout the RPM range, making it ideal for both the track and street. However, the stock 6.4L HEMI pistons can be a weak link when running high boost, which is why we generally recommend keeping the boost under 6-7 psi on a stock engine. To safely run higher boost, we offer drop-in rods and pistons that improve durability and performance.

Modern supercharger systems are designed to maintain daily drivability while delivering massive power. Whether on a stock or built engine, these systems offer significant gains, with smooth street-friendly performance and aggressive power when needed. Aftermarket superchargers from brands like Whipple, Magnuson, and ProCharger are engineered for the 6.4L HEMI, providing factory-like fitment and reliability, making them the perfect upgrade for anyone looking to boost their Scat Pack’s performance across various driving conditions.

Our recommended options:

Gen 6 Whipple 3.0L Supercharger for 6.4L Chargers/ Challengers
- The 3.0L Whipple Supercharger is the ultimate bolt-on power upgrade for Scat Packs, delivering massive horsepower and torque gains while maintaining smooth drivability. With its efficient twin-screw design, it provides instant boost, improved throttle response, and cooler intake temps for consistent performance. Capable of pushing 800+ horsepower with supporting mods, the Whipple transforms your 6.4L HEMI into a Hellcat-crushing beast—perfect for the street or strip. If you’re looking for big power with reliability, the 3.0L Whipple is the answer.
Hellcat Supercharger with our IHI Supercharger Adapter Kit
- Swapping an IHI Hellcat Supercharger onto a Scat Pack 6.4L HEMI is a cost-effective way to add forced induction power while maintaining OEM reliability. With our swap kit, this factory-proven 2.4L blower delivers instant throttle response, strong low-end torque, and 700+ horsepower potential with supporting mods. It integrates seamlessly with the HEMI platform, offering a budget-friendly alternative to aftermarket superchargers while unlocking access to Hellcat tuning, pulley upgrades, and intercooling solutions for even greater performance.
Procharger Stage II 6.4L Supercharger Kit
- The ProCharger Stage 2 Supercharger Kit for the Dodge Scat Pack boosts your 6.4L/392 HEMI by 250+ horsepower, delivering over 700 hp at the crank. With 7 psi of efficient, intercooled boost, this kit offers massive performance gains while keeping charge air temperatures low. The high-efficiency P-1SC-1 supercharger ensures smooth power delivery, and the easy-to-install bracket system simplifies installation. Perfect for anyone looking to enhance street and track performance with reliable, high horsepower.

If you want to take your Scat Pack to the next level, a supercharger is the ultimate upgrade. Whether you’re looking for Hellcat-beating power, better throttle response, or a more thrilling driving experience, forced induction is the way to go.

Upgrading Wheels and Brakes

Upgrading to Weld Racing Wheels and Dusterhoff Racing’s 15-Inch Brake Conversion Kit on your Scat Pack provides substantial performance benefits, particularly for drag racing and high-horsepower builds. The Weld Racing Wheels are designed to reduce rotational mass, allowing the engine to work less to overcome inertia. This results in faster acceleration, better throttle response, and improved overall handling. With less weight at the wheels, your Scat Pack reaches its peak performance more quickly, and the reduced mass also improves braking performance and cornering stability, making your vehicle more responsive and easier to control at higher speeds. Whether you’re launching hard at the drag strip or pushing your car through tight corners on the street, these wheels improve vehicle dynamics and help maintain optimal power delivery.

The 15-inch brake conversion kit is a game-changer for Scat Pack owners looking to maximize performance, especially at the track. This kit allows for the use of drag radials, which provide superior traction due to their larger contact patch. By improving grip, the drag radials reduce wheel spin during hard launches, ensuring more power is put to the ground effectively. With better traction, your Scat Pack can achieve faster, more consistent launches, leading to quicker track times and improved overall performance. The setup minimizes loss of acceleration and maximizes the efficiency of the engine’s output, keeping your vehicle stable and planted under the stress of high-performance driving.

This combination of Weld Racing Wheels, the 15-inch brake conversion kit, and improved traction from drag radials is ideal for those aiming to shave time off their ETs at the track or seeking to harness every ounce of power for street performance. Whether you’re building your Scat Pack for drag racing or street domination, this upgrade provides the performance, reliability, and competitive edge you need to stay ahead of the pack.

Performance Tuning

A custom ECU tune is one of the most effective ways to unlock your Scat Pack’s full potential, fine-tuning the engine’s parameters for better throttle response, increased horsepower, and improved drivability. By optimizing fuel delivery, ignition timing, and air-to-fuel ratios, a proper tune ensures your 6.4L HEMI is running at peak efficiency, delivering more power and sharper acceleration without sacrificing reliability.

Beyond just power gains, a custom tune enhances throttle response, eliminating factory dead spots in the pedal and making acceleration feel crisper and more immediate. The tune also refines the transmission shift points and torque management, improving both performance and smoothness for daily driving or track use.

If you’re adding bolt-on upgrades like a cold air intake, long tube headers, or a supercharger, a tune is essential to recalibrate the ECU and maximize the benefits of those modifications. Without proper tuning, aftermarket parts won’t perform to their full potential, and in some cases, they may even hurt performance or cause drivability issues.

Whether you’re looking for a mild performance bump or a serious power increase, tuning transforms the Scat Pack into a sharper, more responsive machine, making it one of the best investments for getting real-world performance gains without tearing into the engine.