Understanding the 5.7L Hemi Platform

The Dodge Charger RT, equipped with the 5.7L Hemi V8, is a strong foundation for a high-horsepower build. From the factory, the 5.7L produces around 370–390 horsepower depending on the model year, with a cast-iron block, aluminum heads, and a multi-displacement system (MDS) that can complicate high-performance builds. To reach 600+ wheel horsepower (or roughly 700+ at the crank), you need to address airflow, fuel delivery, internal strength, and cooling. The 5.7L’s bore and stroke (3.917 in × 3.578 in) limit its naturally aspirated potential; most RT owners turn to forced induction or nitrous to hit the target. Understanding the platform’s strengths—strong bottom end, decent aftermarket support—and weaknesses—small displacement, restrictive stock intake, and weak rod bolts—is the first step.

The 5.7L Hemi uses a pushrod valvetrain with two spark plugs per cylinder, which helps combustion efficiency. The stock internals are good for about 500–550 crank horsepower before reliability concerns arise. For 600+ wheel horsepower, internal upgrades become mandatory, especially pistons, connecting rods, and head studs. Many builders choose to start with a lower-mileage engine and build it to handle boost, rather than risk pushing a stock block too hard.

Power Adders for 600+ HP

Forced Induction: The Most Direct Path

Supercharging remains the most popular method to break 600 wheel horsepower in a 5.7L Charger RT. A positive displacement blower (like the Whipple 2.9L or 3.0L) or a centrifugal supercharger (ProCharger P-1SC or D-1SC) can deliver substantial gains with a proper intercooler system. The Whipple’s roots-type design offers instant throttle response and low-end torque, making the car feel strong from idle. Centrifugal chargers build boost progressively and can be easier to install as a kit, but may require higher RPM operation to reach peak power.

For 600+ wheel horsepower, you’ll generally need around 8–10 psi of boost on a stock bottom end, but to be safe, forged pistons (custom forged or drop-in from brands like Diamond or Wiseco) and forged H-beam rods (Manley or Callies) are recommended. Head studs (ARP) are essential to keep the cylinder heads sealed under boost. A complete supercharger kit (blower, intercooler, fuel system upgrades, and tune) can range from $5,000 to $8,000 with entry-level centrifugal setups, while high-end Whipple kits can exceed $9,000.

Nitrous Oxide: The Budget Power Shot

Nitrous oxide systems offer a cheaper path to 600+ wheel horsepower, but they require careful jetting, proper fuel enrichment, and a robust engine. A direct-port wet nitrous system (150–250 hp shot) can push the 5.7L over 600 wheel horsepower temporarily, but the risk of detonation and engine damage is higher. Most serious builders use nitrous as a supplement to a built motor, rather than a primary power adder. A quality nitrous kit from Nitrous Express or ZEX costs around $600–$1,200, plus a progressive controller and bottle heater. Supporting mods (fuel system, colder spark plugs, and a dedicated tune) are mandatory.

Naturally Aspirated: The Low-Boost Alternative

Reaching 600 wheel horsepower naturally aspirated on a 5.7L is extremely difficult without major engine work (bore/stroke to 6.1L or 6.4L displacement) or a 6.4L swap. A fully built naturally aspirated 5.7L with ported heads, aggressive camshaft, long-tube headers, and high compression pistons might produce around 450–480 wheel horsepower. To get to 600 wheel, you’d need to add a 6.2L or 6.4L Hemi block or use a combination of nitrous and compression. Many enthusiasts opt for a 6.4L swap (Scat Pack long block) which can cost $3,000–$5,000 used, then add heads and cam to approach 500 wheel naturally aspirated, but still need boost or nitrous to cross 600 wheel. For this article, we assume forced induction is the primary route.

Essential Bolt-On Modifications for Maximum Flow

Even with a supercharger, restrictive stock parts can choke power. The following bolt-ons are strongly recommended before or alongside the boost addition.

Cold Air Intake

A high-quality cold air intake (CAI) reduces intake restriction and lowers intake air temperatures. K&N, Injen, and AFE Power offer proven kits for the Charger RT. Expect a 10–15 horsepower gain on a naturally aspirated car; on a boosted setup, the CAI becomes even more critical because the engine is pulling more air. Sealed intakes that draw air from outside the engine bay are best to avoid heat soak. Budget $300–$500.

Headers and Exhaust

Long-tube headers are the single best bolt-on for exhaust flow on a 5.7L Hemi. American Racing Headers (ARH) and Kooks produce stainless steel 1¾” or 1⅞” primary tubes that can add 25–40 horsepower naturally aspirated, and even more on a boosted engine. Paired with a high-flow mid-pipe (catted or catless, depending on emissions laws) and a cat-back exhaust (Borla, MagnaFlow, Corsa), the exhaust system becomes a free-flowing path. Expect $1,200–$2,000 for headers and $800–$1,500 for a cat-back system.

Ported Throttle Body & Intake Manifold

The factory 80mm throttle body can be upgraded to a 90mm or 95mm unit from Fastman or CNC ported units to improve throttle response. The intake manifold on the 5.7L can be port-matched or replaced with a larger unit (like the Holley Hi-Ram for carbureted builds, but for a street car, a ported stock manifold or a 6.4L intake swap yields good results). Gains are modest (5–15 hp) but complement the supercharger’s demand for air. Budget $400–$800 for these mods.

Supporting Upgrades: Building a Bulletproof Drivetrain

Reaching 600+ wheel horsepower requires more than just an engine build—the transmission, axles, fuel system, and cooling must handle the increased load.

Fuel System Upgrades

The stock fuel injectors (21 lb/hr) and pump are insufficient for boost. You’ll need high-flow injectors (60–85 lb/hr for non-ethanol, or 100+ lb/hr for E85) and a larger in-tank pump (e.g., DW400 or AEM 340lph). For big power, a return-style fuel system with a Fuelab or Aeromotive regulator is recommended. E85 conversion can reduce knock and allow more timing, but requires upgrading stainless steel lines and rubber hoses. Total fuel system investment: $800–$2,500.

Cooling System: Keeping the Heat Down

A supercharger adds significant heat to the intake charge; a properly sized intercooler (air-to-water or air-to-air) is included in most kits. For the engine coolant, a high-performance radiator (Mishimoto, AFCO) with dual electric fans and a 180°F thermostat helps maintain consistent temperatures. Upgraded oil cooler (Mocal or Setrab) and transmission cooler are also wise for track use. Budget $500–$1,500.

Transmission & Drivetrain

Charger RTs use the ZF 8HP70 eight-speed automatic, which is robust but can slip under 600+ wheel torque in stock form. A performance torque converter (Yank or Circle D) with a higher stall speed (2800–3200 RPM) improves power delivery. A transmission cooler, updated valve body, and a custom tune for shift points are essential. For manual swaps (rare), the Tremec T-56 or TR-6060 can handle the power, but conversion is expensive. The rear end (7.25” differential) may need upgrades to a 8.8” or 9” unit from a Dodge Charger Pursuit or aftermarket (Strange, Moser). Budget $1,500–$4,000 for transmission work and another $1,500 for rear end upgrades if needed.

Suspension & Brakes

More power demands better stopping power. Upgrade to six-piston Brembo brakes from the SRT models (common swap) or aftermarket big brake kits (Baer, Wilwood). Lowering springs (Eibach, H&R), adjustable sway bars, and stronger control arms help plant the power during launches. Budget $1,000–$3,000, but you can prioritize brakes first.

Cost Breakdown & Realistic Budgeting

Below is a detailed cost breakdown for a 600+ wheel horsepower build on a Dodge Charger RT. Prices include parts and labor (estimated at $100–$150/hour). DIY labor can save $2,000–$4,000.

  • Cold Air Intake – $300–$500 (parts) + $100–$200 installation
  • Long-Tube Headers & Exhaust – $1,200–$2,000 (headers) + $800–$1,500 (cat-back) + $600–$900 labor
  • Supercharger Kit (Whipple/ProCharger) – $5,500–$9,000 (parts) + $1,500–$2,500 installation & tuning
  • Fuel System Upgrades – $800–$2,500 (injectors, pump, lines) + $400–$800 labor
  • Engine Internals (forged pistons/rods, head studs) – $1,500–$3,000 (parts) + $2,000–$3,500 labor if installed with engine removal
  • ECU Tune (HP Tuners / DiabloSport) – $500–$1,000 (including custom tuning by a professional)
  • Transmission Upgrades (converter, cooler, tune) – $1,500–$3,000 (parts) + $600–$1,200 labor
  • Cooling System (radiator, intercooler if not included, oil cooler) – $500–$1,500 (parts) + $300–$600 labor
  • Brake Upgrade – $1,200–$3,000 (parts) + $300–$600 labor
  • Suspension (optional but recommended for traction) – $1,000–$2,000 (parts) + $400–$800 labor

Typical total (with professional labor): $15,000–$25,000+. Doing the installation yourself and using a milder supercharger kit can bring the total to around $10,000–$13,000, but that assumes no internal engine work (risky for long-term reliability). For a reliable 600+ wheel horsepower build, budgeting around $18,000–$22,000 is realistic. Many owners spend on the high side because they chase reliability.

Final Considerations: Reliability, Tuning & Professional Help

Hitting 600+ wheel horsepower on a Dodge Charger RT is an exhilarating achievement, but the journey demands meticulous planning. Custom tuning is non-negotiable—a generic “canned” tune often runs lean or too aggressive on timing. Use a reputable tuner like Hemifever, Jay Greene (Fastlane), or local chassis dyno specialists who have experience with boosted Hemis. Log your engine’s parameters (fuel pressure, air/fuel ratio, knock retard) regularly.

Consider building the engine to handle 800+ horsepower even if you only tune for 600 wheel—this creates a safety margin. A forged internal build can cost $3,000–$5,000 in parts alone but prevent catastrophic failure. Also, join forums like LXForums or Charger Forums to learn from other builders’ experiences.

Finally, remember that achieving 600+ horsepower on pump gas (91-93 octane) is possible with a mild tune and intercooling, but switching to E85 or a water-methanol injection system can dramatically reduce knock and allow more timing. Start with a solid platform, invest in supporting mods, and work with professionals. Your Charger RT can become a reliable, streetable monster—if you respect its limits.