Introduction: The 600 HP 5.7 HEMI Build

The Dodge Challenger equipped with the 5.7-liter HEMI V8 is a fantastic platform for a high-horsepower project. While the engine is robust from the factory, cracking the 600 wheel-horsepower mark demands more than just a tune and a cold-air intake. To reliably handle the increased cylinder pressure and stress, forged internals become a necessity, not an option. This article provides a comprehensive, line-item cost breakdown for building a 600 HP Dodge Challenger 5.7 HEMI with forged internals, covering every component from the short block to the final dyno pull. Whether you're planning a weekend warrior or a street/strip bruiser, understanding where your budget goes is the first step to a successful build.

Why Forged Internals Matter for 600 HP

The stock cast pistons and connecting rods in the 5.7 HEMI are perfectly capable at stock power levels, but they become a weak link under sustained high boost or significant naturally aspirated upgrades. Forged internals—pistons, rods, and crankshaft—offer superior strength, heat resistance, and fatigue life. At 600 horsepower, the risk of a bent rod or cracked piston increases exponentially. Investing in forged components is insurance against catastrophic engine failure. For a thorough technical discussion on forged vs. cast internals, Engine Builder Magazine offers an excellent deep dive.

Forged Pistons

Forged pistons are machined from a single billet of aluminum alloy, providing a denser, stronger structure than cast alternatives. They handle higher combustion pressures and temperatures without distorting. For a 600 HP build, a 2618 alloy forged piston (such as those from Diamond Pistons) is the standard choice.

Forged Connecting Rods

The connecting rods take immense stress during the power stroke. Forged rods, typically made from 4340 steel, offer significantly higher tensile strength than powdered-metal factory rods. Brands like K1 Technologies manufacture rods specifically designed for high-boost HEMI applications.

Forged Crankshaft

While the factory 5.7 HEMI crankshaft is nodular iron and fairly strong for stock levels, a forged 4340 crankshaft provides added safety margin for sustained high power and higher RPM operation. The increased rigidity helps prevent flex and reduces harmonic vibration.

Complete Cost Breakdown

The following breakdown is based on current retail pricing for quality aftermarket parts and professional labor. Prices can vary based on brand, vendor, and regional labor rates. All estimates are for parts only unless noted.

Engine Components (Top End)

The cylinder heads, camshaft, and intake manifold are where the most power is unlocked from the 5.7 HEMI. These upgrades work together to increase airflow and optimize the powerband.

  • High-Performance Camshaft: Expect to pay $1,000–$1,400 for a custom-ground or off-the-shelf performance camshaft designed for the HEMI's VVT system. A 224/228 duration on a 112 LSA is a solid starting point.
  • Upgraded Cylinder Heads (CNC Ported): Budget $1,500–$2,200 for a set of CNC-ported heads that flow significantly better than stock. This includes new valves, springs, and retainers.
  • Aftermarket Intake Manifold: A single-plane or high-rise design (from Edelbrock or similar) runs $600–$900. It improves airflow at higher RPMs.
  • High-Flow Exhaust Headers: Long-tube headers in 1-⅞-inch primary tubes cost around $400–$700. Pair them with a full 3-inch exhaust to reduce backpressure.
  • Head Gaskets & Bolts: MLS head gaskets and ARP head studs add about $200–$300 for reliability.

Forged Internals (Bottom End)

This is the heart of the reliability upgrade. The price reflects quality racing-grade components suitable for 600–700 HP.

  • Forged Pistons: $700–$1,000 for a set of eight pistons with wrist pins and rings. Expect to select a compression ratio between 9.5:1 and 10.5:1 for forced induction or high-compression N/A builds.
  • Forged Connecting Rods: $800–$1,100 for a set of H-beam 4340 steel rods. These are lighter and stronger than factory rods.
  • Forged Crankshaft: $1,200–$1,600 for a 4340 forged crank that accepts HEMI rod journals. It eliminates any harmonic concerns and allows higher RPM safely.
  • Performance Engine Bearings: $150–$250 for main and rod bearings (e.g., Clevite or ACL). These are crucial for proper oil clearance and longevity.

Fuel System Upgrades

At 600 HP, the stock fuel pump and injectors will be insufficient. You need to deliver enough fuel volume and pressure at high demand.

  • High-Performance Fuel Injectors: $500–$700 for a set of 80–100 lb/hr injectors. Upgrade to a return-style system if planning for future power levels.
  • Upgraded Fuel Pump: $400–$600 for a 340 LPH or larger in-tank pump. A boost-referenced fuel pressure regulator is often included in quality pump kits.
  • Fuel Pressure Regulator & Lines: $300–$500 for an adjustable regulator and PTFE-style lines. Do not skimp on fuel delivery.

Tuning and Software

No build is complete without proper calibration. Tuning unlocks the potential and ensures safety. Expect to spend money on both software and professional time.

  • Performance Tuning Software: $400–$600 for HP Tuners or DiabloSport platform. This allows you to adjust fuel, spark, and transmission shift points.
  • Dyno Tuning Session: $400–$700 for a full session on a load-bearing dyno. A skilled tuner will optimize for your specific fuel octane.

For a deep look at HEMI tuning specifics, HP Tuners has extensive support for the 5.7 HEMI.

Labor Costs

Labor rates vary widely. A reputable performance shop will charge between $100 and $150 per hour. Expect the following tasks to be billed:

  • Engine Disassembly & Inspection: $600–$1,000
  • Short Block Assembly (Pistons, Rods, Crank): $800–$1,200 (including ring gaps, bearing clearances)
  • Top End Assembly (Heads, Cam, Timing): $400–$700
  • Installation of Fuel System & Accessories: $300–$600
  • Dyno Tuning & Road Testing: covered above

Total labor for a full teardown and rebuild with upgrades: $2,000–$3,500. We'll use $2,500 for our estimate.

Miscellaneous Parts

These items are easy to overlook but essential for a successful build.

  • Gaskets and Seals Full Set: $200–$300 (Fel-Pro or OEM equivalent)
  • Oil and Fluids: $250–$400 for break-in oil, synthetic transmission fluid, coolant, and power steering fluid.
  • Hardware (ARP fasteners, new bolts): $300–$600 for main studs, head studs, rod bolts, and misc hardware.
  • Spark Plugs & Wires: $100–$200 (step colder plugs recommended)
  • Thermostat & Water Pump: $100–$200
  • Miscellaneous (hoses, clamps, wiring, sensors): $200–$400

Total Estimated Cost

Adding the realistic mid-range figures:

  • Engine Components (Top End): $3,800
  • Forged Internals (Bottom End): $3,200
  • Fuel System Upgrades: $1,800
  • Tuning and Software: $1,100
  • Labor Costs: $2,500
  • Miscellaneous Parts: $1,200

Grand Total Estimate: $13,600

This is a realistic budget for a professionally built 600 HP 5.7 HEMI with forged internals. If you can perform the engine assembly yourself, you can save $1,500–$2,500 in labor. Conversely, a fully turnkey build from a top-tier shop could approach $16,000–$18,000 with premium components and porting.

Optional Upgrades to Consider

If your budget allows, these additions can improve driveability, reliability, and future power potential.

  • High-Volume Oil Pump: $200–$350 (improves oiling at high RPM)
  • Upgraded Timing Chain & Tensioner: $150–$250 (stock chains stretch under high torque)
  • Forced Induction Preparation: If you plan to add a supercharger later, choose a lower compression piston (9.5:1) and a bigger fuel system now.
  • Cold-Air Intake & Throttle Body: $300–$600 (supporting mods that add 10–15 HP)

Conclusion

Building a 600 HP Dodge Challenger 5.7 HEMI with forged internals is a rewarding undertaking that requires careful budgeting. With a total investment around $13,600 (parts and labor), you can create a durable engine capable of delivering thrilling street and track performance. The key is to prioritize the bottom end—forged pistons, rods, and crank—before stacking on top-end airflow mods and tuning. Start by sourcing quality parts from trusted suppliers like Summit Racing and dedicated HEMI specialists, and always invest in a professional dyno tune. Your Challenger will thank you with reliable, tire-shredding power for years to come.