Want more power from your 5.7 Hemi? You’re sitting on a goldmine of untapped potential. The iconic Chrysler powerplant has proven itself as a reliable workhorse in Rams, Chargers, Challengers, and 300s—but with the right upgrades, it can transform from respectable to remarkable. Let’s dive into the most effective ways to wake up your Hemi without breaking the bank (or your engine).
Understanding Your 5.7 Hemi’s Potential
The factory 5.7 Hemi delivers impressive numbers right out of the box—around 345-395 horsepower depending on your application. But Chrysler left plenty on the table for enthusiasts like you. With strategic modifications, you can push well beyond 500 wheel horsepower while maintaining reliability.
What makes the 5.7 Hemi so responsive to upgrades? Its hemispherical combustion chambers promote excellent airflow, while the robust block can handle significant power increases. The key is approaching modifications systematically—starting with the basics before diving into more complex upgrades.
Entry-Level Bolt-On Upgrades: The Gateway to Power
Cold Air Intakes: Your First Performance Step
The stock airbox is restrictive, plain and simple. Cold air intakes offer an immediate performance boost by:
- Reducing intake air temperatures by 30-50°F
- Improving airflow by up to 50% over stock
- Adding 10-15 wheel horsepower when paired with proper tuning
- Enhancing throttle response for better driving feel
Installation takes about an hour with basic tools, making this the perfect weekend upgrade. Look for systems with reusable filters and proper heat shielding to prevent hot underhood air from robbing power.
Throttle Body Upgrades: Removing the Bottleneck
Your engine breathes through its throttle body, and the stock unit leaves room for improvement. Upgrading to a larger diameter throttle body like BBK’s 85mm unit offers:
- 12% larger bore diameter than stock
- 10-12 WHP gains when combined with other intake mods
- Improved throttle response throughout the RPM range
- Direct bolt-on installation with no permanent modifications
Most aftermarket throttle bodies maintain factory electronics for seamless integration, though tuning maximizes benefits.
Exhaust System Enhancements: Let Your Hemi Breathe
The restrictive factory exhaust system creates unnecessary backpressure. A performance exhaust overhaul includes:
- Headers: Long-tube headers improve exhaust scavenging, particularly in the crucial mid-range RPMs where you feel power daily.
- High-Flow Cats: Reduce emissions system restrictions while staying emissions compliant.
- Cat-Back Systems: Complete systems like aFe Power’s 3″ setup deliver +22 WHP and +26 lb-ft of torque on the dyno.
The sound improvement alone makes exhaust upgrades worthwhile—from subtle rumble to aggressive growl depending on your preference.
Intermediate Performance Upgrades: Serious Power Gains
Camshaft Upgrades: The Heart of Your Build
Nothing transforms a Hemi’s character like a cam swap. Aftermarket camshafts from companies like Comp Cams offer:
- Up to 0.596″ intake lift (significantly higher than stock)
- Extended duration for better high-RPM breathing
- Power gains of 40-60 WHP when properly supported
- Distinctive, aggressive idle and exhaust note
This isn’t a beginner’s mod—camshaft upgrades require supporting modifications like valve springs, pushrods, and careful tuning. However, the transformation is dramatic, particularly when paired with other breathing improvements.
Pro tip: Consider upgrading to Hellcat lifters while performing cam work—they eliminate the factory hydraulic roller’s RPM limitations and reduce the risk of MDS lifter failure.
Cylinder Head Optimization: Maximizing Airflow
The factory 5.7 Hemi heads offer decent performance, but porting or upgrading unleashes significant power:
- CNC-ported factory heads can flow 380+ cfm at 0.600″ lift
- “Eagle” heads from 2009+ models offer a direct bolt-in upgrade
- Aftermarket options like TFS Super 23s provide thicker decks for boosted setups
- Potential gains of 30-40 WHP when combined with proper cam timing
For those on a budget, a professional port job on your existing heads offers excellent return on investment compared to complete replacement.
Intake Manifold Swaps: From 5.7 to 6.4
One of the most effective bolt-on upgrades is swapping your restrictive 5.7L intake manifold for the superior 6.4L (Apache/392) design. This upgrade offers:
- Larger plenum volume for improved high-RPM breathing
- Optimized runner length and design for better torque curve
- 15+ WHP gains on otherwise stock engines
- Improved throttle response across the powerband
Complete swap kits include all necessary components, making this a straightforward weekend project with impressive results.
Advanced Performance Upgrades: Breaking the 500HP Barrier
Forced Induction: Superchargers vs. Turbochargers
Nothing transforms a 5.7 Hemi like boost. You have two primary options:
Supercharger Kits:
- RIPP’s Vortech V3 system can push a stock Charger from 320 WHP to 528 WHP at just 6-8 psi
- Edelbrock’s E-Force TVS uses efficient Eaton rotors for 500+ WHP with OEM-like drivability
- Whipple’s twin-screw designs excel at low-end torque—ideal for trucks and street applications
- Immediate throttle response with minimal lag
Turbocharger Systems:
- ON3 Performance’s twin-turbo kit supports 400-1000+ WHP depending on your build level
- Greater top-end potential than superchargers
- More efficient at higher power levels
- Requires more supporting modifications
Both approaches require fuel system upgrades and professional tuning, but deliver transformative performance.
Stroker Kits: Bigger Is Better
Want to transform your 5.7 into something bigger? Stroker kits increase displacement for substantial torque gains:
- Molnar Technologies’ 4.050″ stroker kit expands to 392 cubic inches
- Forged internals support up to 1,200 HP in fully built applications
- 15-20% torque increase throughout the powerband
- Requires machine work and professional assembly
This modification fundamentally changes your engine’s character, emphasizing torque production while preparing for future power adders.
Nitrous Oxide: Instant Power On Demand
Nitrous offers the best power-per-dollar ratio of any modification when implemented correctly:
- Nitrous Outlet’s 90mm plate system adds 50-200+ HP with the push of a button
- Direct-port systems ensure even cylinder-to-cylinder distribution
- Can be used as a standalone mod or complement to other upgrades
- Perfect for drag applications with adjustable power levels
Proper tuning and adequate fuel supply are critical—running lean with nitrous is a recipe for disaster.
The Critical Role of ECU Tuning
No matter which upgrades you choose, professional tuning is the glue that holds everything together. The 5.7 Hemi uses a sophisticated torque-based engine management system that requires specialized knowledge.
- HP Tuners software allows adjustment of fuel maps, ignition timing, and torque management
- Proper AFR (air-fuel ratio) and timing optimization unlock hidden power
- Torque-based calibrations require reconciling commanded vs. actual torque
- Dyno tuning ensures reliable, consistent performance
Even basic bolt-ons need tuning adjustments to realize their full potential. Standalone ECUs like Holley Dominator become necessary for builds exceeding 1,000 HP.
Performance Upgrades Comparison Table
| Upgrade Type | Cost Range | Potential Power Gain | Installation Difficulty | Emissions Compliant |
|---|---|---|---|---|
| Cold Air Intake | $300-500 | 10-15 WHP | Easy (DIY) | Usually Yes |
| Throttle Body | $300-450 | 8-12 WHP | Easy (DIY) | Yes |
| Cat-Back Exhaust | $700-1,500 | 15-25 WHP | Moderate | Yes |
| Headers | $800-1,800 | 20-30 WHP | Difficult | Varies by design |
| Camshaft Package | $1,500-2,500 | 40-60 WHP | Professional | No |
| CNC Ported Heads | $1,800-3,000 | 30-40 WHP | Professional | Yes |
| 6.4L Intake Swap | $900-1,200 | 15-20 WHP | Moderate | Yes |
| Supercharger Kit | $5,000-8,000 | 150-200+ WHP | Professional | Varies by kit |
| Turbo System | $4,500-9,000 | 150-400+ WHP | Professional | Usually No |
| Stroker Kit | $4,000-7,000 | 50-80 WHP | Professional | Varies |
| Nitrous System | $600-1,500 | 50-200+ WHP | Moderate | Yes (when inactive) |
Building Your Upgrade Path: Strategic Approach
Rather than randomly adding parts, follow this proven upgrade path for maximum results:
Stage 1: Foundation (20-40 WHP gain)
- Cold air intake
- Cat-back exhaust
- Professional tune
- Throttle body upgrade
Stage 2: Serious Power (60-90+ WHP gain)
- Headers (long-tube preferred)
- 6.4L intake manifold swap
- Upgraded fuel injectors
- Revised tune
Stage 3: Advanced Performance (100-150+ WHP gain)
- Camshaft package with supporting valvetrain
- CNC ported cylinder heads
- High-flow fuel system
- Custom dyno tune
Stage 4: Maximum Power (200-400+ WHP gain)
- Forced induction (supercharger or turbo)
- Forged internal components
- Upgraded transmission/driveline
- Race fuel or E85 capability
By following this progression, you’ll avoid wasting money on parts that won’t work together while building a coherent, reliable package.
Real-World Build Examples
Daily Driver Enhancement
- Cold air intake
- 85mm throttle body
- Cat-back exhaust
- Performance tune
Result: +35-45 WHP, improved throttle response, better sound, no sacrifice in reliability
Weekend Warrior
- Complete intake/exhaust package
- 6.4L intake manifold swap
- Mild camshaft upgrade
- 3.91 rear gears
Result: +80-100 WHP, transformed character, aggressive sound, still streetable
Track/Strip Dominator
- RIPP supercharger kit
- Forged internals
- CNC ported heads
- Full supporting mods
Result: 500-600+ WHP, quarter-mile times in the 11s, still capable of daily driving
Supporting Modifications
Don’t overlook these critical supporting upgrades when building power:
- Cooling System Upgrades: Higher-capacity radiator, electric fans, and coolant additives prevent heat-related issues.
- Transmission Reinforcements: Factory automatics require shift kit and torque converter upgrades beyond 450 WHP.
- Driveline Components: Upgraded driveshafts, differentials, and axles prevent expensive failures.
- Fuel System: High-flow pumps and injectors prevent lean conditions that can destroy engines.
- Suspension and Braking: Additional power requires improved stopping and handling capabilities.
The 5.7 Hemi responds remarkably well to performance upgrades, with each dollar spent yielding impressive results when applied strategically. Whether you’re looking for modest improvements or planning to build a street monster, the right combination of parts and tuning will unleash your Mopar’s hidden potential.
Are you ready to wake the sleeping giant under your hood?
