Introduction: Building a Stronger 6.4 Hemi

The 6.4-liter Hemi V8, found in Dodge Charger Scat Packs, Challenger R/T Scat Packs, and Ram 2500/3500 trucks, is a formidable engine right out of the box. With 485 horsepower and 475 lb-ft of torque in car applications, it offers a solid foundation for further performance gains. One of the most effective paths to unlock additional power is a camshaft upgrade paired with complementary intake and exhaust modifications. This article breaks down the real-world costs of upgrading your 6.4 Hemi with a Comp Cams camshaft, a K&N cold air intake, and an MBRP exhaust system. We’ll cover part pricing, labor, tuning, and hidden expenses so you can budget accurately and decide whether this combination fits your goals.

Why Upgrade the 6.4 Hemi’s Camshaft, Intake, and Exhaust?

The factory camshaft in the 6.4 Hemi is designed for a balance of power, fuel economy, and emissions compliance. Aftermarket camshafts from companies like Comp Cams increase valve lift and duration, allowing the engine to breathe more freely at high RPM. This unlocks significant horsepower—often 50 to 100 wheel horsepower when paired with matching induction and exhaust upgrades. A K&N cold air intake reduces restriction at the air filter and provides denser, cooler air to the throttle body. The MBRP exhaust system reduces back pressure and improves scavenging, further helping the engine expel spent gases. Together, these three modifications create a synergistic performance gain that transforms the driving experience.

Component Deep Dive: What You’re Buying

Comp Cams for the 6.4 Hemi

Comp Cams offers several profiles for the 6.4 Hemi, ranging from mild street cams to aggressive race-oriented grinds. A popular choice is the Comp Cams 274HR or 283HR series, which provide noticeable mid-range and top-end power without requiring extensive valvetrain modifications. Prices vary by camshaft type:

  • Hydraulic roller camshaft (mild): $350–$550
  • Performance hydraulic roller camshaft: $550–$900
  • Street/strip or custom grind: $700–$1,200

Some cam profiles may require upgraded valve springs, pushrods, and retainers. Factor in an additional $200–$400 for a valve spring kit if your chosen cam demands higher spring pressure. Comp Cams provides detailed specifications on each cam’s lift, duration, and lobe separation angle; choose based on your driving style and whether you plan to keep the engine naturally aspirated or add forced induction later.

K&N Cold Air Intake

K&N’s intake systems for the 6.4 Hemi feature a high-flow cotton gauze filter, a larger diameter intake tube, and a heat shield that separates the filter from engine bay heat. They are CARB-compliant on most vehicle applications. Pricing:

  • Standard K&N intake kit: $300–$450
  • Performance Series or Blackhawk intake: $450–$700

Installation is straightforward, usually requiring only basic hand tools. The intake alone can add 10–15 horsepower on a stock engine, and it will support the increased airflow demands of a cam and exhaust upgrade. K&N filters are reusable, which lowers long-term replacement costs.

MBRP Exhaust System

MBRP manufactures exhaust systems known for their mandrel-bent tubing, T-304 stainless steel or aluminized steel construction, and aggressive sound profiles. For the 6.4 Hemi, a cat-back system is the most common upgrade. Options include:

  • Cat-back exhaust (axle-back + intermediate pipe): $400–$800
  • Full exhaust system (header-back or turbo-back if applicable): $800–$1,500

MBRP offers both single and dual rear exit configurations, with muffler options ranging from moderately aggressive to race-style. The exhaust alone can provide 5–15 horsepower, but its primary benefit with a cam upgrade is reducing back pressure and letting the engine breathe out efficiently. Expect a deeper tone and more pronounced idle characteristics, especially with a performance cam.

Installation Labor: What You’ll Pay a Shop

Labor costs vary dramatically based on your location and the shop’s hourly rate (typically $100–$150 per hour). Here’s what each job entails:

Camshaft Installation

Swapping a cam in a 6.4 Hemi is a major job that often requires 8–12 hours of labor, because the front of the engine must be disassembled (timing cover, timing chain, phaser, etc.). Many shops recommend replacing the timing chain, tensioners, and oil pump at the same time. Expect:

  • Basic cam swap (no valve spring removal): $800–$1,200
  • Cam swap including valve spring upgrade: $1,000–$1,500

Intake and Exhaust Installation

These are much simpler. A cold air intake install takes 1–2 hours ($100–$300). An MBRP cat-back exhaust install takes 2–3 hours ($200–$450). If you do both at the same time, some shops offer a small discount on combined labor.

The Critical Role of Tuning

After installing a performance cam, intake, and exhaust, the engine’s air/fuel ratio and ignition timing will be far from optimal. The factory ECU cannot compensate for the increased airflow. A custom tune is mandatory to avoid lean conditions, detonation, and check engine lights. Tuning costs include:

  • Handheld tuner (e.g., DiabloSport, HP Tuners): $400–$700
  • Custom remote tune by a reputable shop: $300–$600
  • Dyno tune at a shop: $500–$800

Budget at least $700–$1,200 for a proper tuning solution. Without a tune, you risk engine damage and will not realize the full performance potential. Many tuners offer remote calibrations via email, which is a cost-effective option if you cannot get to a dyno.

Expected Performance Gains

With a moderate Comp Cams camshaft, K&N intake, and MBRP cat-back exhaust, plus a proper tune, a 6.4 Hemi typically gains 40–70 wheel horsepower and 30–50 lb-ft of torque. Aggressive cam profiles can push gains to 80–100 wheel horsepower. The powerband shifts upward, with peak torque moving 500–1,000 RPM higher. The engine will also have a distinct “lope” at idle, which many enthusiasts enjoy.

Keep in mind that additional supporting modifications (porting the intake manifold, larger throttle body, high-flow catalytic converters or headers) can increase gains further but will raise costs. For a well-rounded street build, the cam/intake/exhaust combination offers one of the best horsepower-per-dollar ratios available.

Hidden Costs and Additional Parts

When planning your budget, account for these often-overlooked expenses:

  • Gaskets and seals: Valve cover gaskets, timing cover gasket, etc. – $30–$80
  • Coolant and oil: Topping off or replacing fluids after cam install – $30–$60
  • Valve springs, retainers, and pushrods: If cam requires – $200–$500
  • Timing chain and tensioner: Recommended replacement during cam swap – $150–$300
  • Spark plugs: Fresh plugs for best performance – $40–$80
  • Labor for tuning (if not included): See tuning section above

Adding these items can increase total cost by $400–$1,000 depending on parts needed.

DIY vs Professional Installation: What’s Right for You?

Doing the work yourself can save $1,000–$2,000 in labor. However, a cam swap on a 6.4 Hemi is not a beginner project. You’ll need specialty tools (harmonic balancer puller, camshaft tool, torque wrench, etc.), a safe workspace, and mechanical experience. Mistakes can lead to timing chain failure or damaged cylinder heads. If you have moderate engine-building experience and a factory service manual, DIY is viable. Otherwise, paying a professional shop is a wise investment. Intake and exhaust are much easier—any enthusiast with basic tools can install them in a driveway.

Total Cost Scenarios: From Budget to Premium

Here are three realistic build scenarios to help you plan your budget. Prices include parts, labor, tuning, and common extras.

Budget Street Build

  • Mild Comp Cams camshaft: $500
  • Standard K&N intake: $350
  • MBRP cat-back exhaust: $600
  • DIY installation (intake/exhaust) + shop cam install: $1,200
  • Handheld tuner + email tune: $800
  • Gaskets, fluids, valve springs: $400
  • Total: ~$3,850

Mid-Range Performance Build

  • Performance Comp Cams camshaft: $750
  • K&N Blackhawk intake: $550
  • MBRP full exhaust: $1,100
  • Shop labor for all (cam + intake + exhaust): $1,800
  • Dyno tune: $700
  • Valve springs, pushrods, timing chain: $600
  • Total: ~$5,500

High-End Street/Strip Build

  • Custom grind Comp Cams camshaft: $1,000
  • K&N intake with carbon fiber tube: $700
  • MBRP header-back exhaust: $1,500
  • Full shop labor plus cylinder head porting (optional): $2,500
  • Dyno tune and data logging: $800
  • Heavy-duty valve train kit: $1,000
  • Total: ~$7,500

Note: The high-end scenario assumes you’re also upgrading cylinder heads or going all-out. Most 6.4 Hemi owners will spend between $3,500 and $6,000 for a balanced, reliable build.

Warranty and Emissions Considerations

Installing a performance cam, intake, and exhaust will void your factory powertrain warranty on affected components. Some states (California, New York, etc.) have strict emissions laws that prohibit modifications to catalytic converters or ECU calibrations unless CARB-approved parts are used. K&N intake and MBRP exhaust are often CARB-compliant, but camshafts and tuning generally are not. Check local regulations before purchasing. If the vehicle is still under warranty, consider waiting until the warranty expires, or be prepared to cover repair costs out of pocket.

Final Thoughts

Upgrading your 6.4 Hemi with a Comp Cams camshaft, K&N intake, and MBRP exhaust is a proven way to add serious horsepower and create an exhilarating driving experience. The costs range from under $4,000 for a budget-friendly DIY approach to over $7,000 for a top-tier professional build. The key is to plan thoroughly, account for tuning and hidden parts, and choose components that match your performance goals and driving style. Whether you turn wrenches yourself or trust a professional shop, this combination delivers one of the most satisfying transformations available for the 6.4 Hemi.

For further reading, check out Comp Cams’ official product page for 6.4 Hemi camshaft options, K&N’s application search for vehicle-specific intakes, and MBRP’s exhaust lineup to confirm fitment. For installation guidance, forums like Ram Forum offer firsthand experiences from owners who have completed similar builds.