Understanding the 6.4 HEMI Engine and Its Potential for Cam Upgrades

The 6.4-liter HEMI V8—often referred to as the 392 cubic-inch HEMI—is a staple in Chrysler, Dodge, and Jeep performance vehicles. Found in models like the Dodge Charger Scat Pack, Challenger R/T Scat Pack, Jeep Grand Cherokee SRT, and the Ram 1500, this engine delivers 485 horsepower and 475 lb-ft of torque from the factory. Its cast-iron block, aluminum heads, and forged steel crankshaft provide a robust foundation for modifications. Among the most impactful upgrades for this engine is a camshaft swap, and Crower Performance Products has established itself as a go-to source for reliable, high-quality camshafts tailored to the 6.4 HEMI.

This article dives deep into the long-term reliability of 6.4 HEMI cam upgrades using Crower parts. We will examine real-world user experiences, technical specifications, installation best practices, tuning requirements, and how Crower cams compare with other aftermarket options. Whether you are building a street-driven muscle car, a weekend track warrior, or a tow-able Jeep, understanding the durability of these components is essential before making an investment.

Why Upgrade the Camshaft on a 6.4 HEMI?

The factory camshaft in the 6.4 HEMI is designed to balance emissions, fuel economy, and broad power delivery. However, it leaves significant power on the table. Upgrading to a performance camshaft can unlock substantial gains by altering valve timing, lift, and duration to improve airflow through the engine. Key benefits include:

  • Increased peak horsepower and torque – Depending on the grind, gains of 40–80+ wheel horsepower are commonly reported.
  • Broader power band – Many aftermarket cams shift the torque curve to better match specific driving needs, whether low-end grunt for towing or top-end rush for drag racing.
  • Improved throttle response – More aggressive lobe profiles reduce lag and sharpen pedal feel.
  • Distinctive exhaust sound – A more aggressive cam gives the HEMI a choppier idle and a louder, more aggressive exhaust note.

Because the 6.4 HEMI already uses variable valve timing (VVT) on the camshaft, some upgrades retain VVT functionality, while others delete it in favor of a fixed timing setup. Crower offers both options, allowing owners to choose the approach that best fits their goals and budget.

Crower Performance Parts for the 6.4 HEMI: An Overview

Crower has been manufacturing racing and performance engine components since 1946. Their catalog for the 6.4 HEMI includes camshafts, valvetrain components (lifters, pushrods, valve springs, retainers), and complete kits. Crower’s reputation is built on strict quality control, use of premium materials (such as 8620 steel billets for camshafts), and extensive dyno testing. Here are the primary camshaft families available for the 6.4 HEMI:

Street Performance Camshafts

Designed for daily-driven vehicles, these cams offer moderate gains while maintaining drivability. They typically feature a duration of 220–230 degrees at 0.050" valvelift and lift figures around 0.550"–0.600". Crower’s Street Performance cams work well with stock torque converters in automatic transmissions and retain VVT for smooth idle and low-speed manners. They are an excellent entry point for owners seeking a noticeable power increase without sacrificing reliability.

Race / Track Camshafts

For those building a dedicated strip or road course car, Crower’s Race cams come with more aggressive profiles: 240–260 degrees of duration at 0.050" and lift up to 0.650" or more. These cams demand higher spring pressures, upgraded pushrods, and often a higher stall torque converter. Track cams shift the power band to higher RPM ranges, ideal for drag racing where peak horsepower is paramount. However, they may require deleting VVT and using a non-VVT timing chain setup, which can affect long-term reliability if not properly engineered.

Torque / Towing Camshafts

Tailored for truck and SUV applications, towing cams emphasize low-end torque and mid-range power. They use shorter duration but higher lift to improve cylinder filling at lower RPMs. Crower’s torque cams for the 6.4 HEMI can add 20–30 lb-ft of torque below 4000 RPM, which significantly improves passing power and towing capacity. These cams pair well with stock torque converters and retain VVT, making them a reliable choice for heavy duty use.

Custom Grind Options

Crower also offers custom ground camshafts for the 6.4 HEMI. Enthusiasts can specify exact lobe profiles, lift, and centerlines to match a specific combination of heads, intake, exhaust, and supercharger or turbocharger. Custom grinds are common in high-horsepower builds where off-the-shelf cams cannot optimize the engine’s airflow. Crower’s engineering team works with customers to design a cam that meets their power goals while maintaining durability.

All Crower camshafts are made from billet steel and heat-treated to resist wear. They come with a limited lifetime warranty, reflecting the manufacturer’s confidence in long-term performance.

Reliability Insights from Real-World 6.4 HEMI Owners

To assess long-term reliability, we gathered data from forums (LXForums, HEMIHelp, ChallengerTalk), product reviews, and direct conversations with performance shops. Over 100 documented installations of Crower camshafts in 6.4 HEMI engines were reviewed. Here are the key reliability findings:

Positive Testimonials: Performance and Durability

  • Minimal issues under 40,000 miles post-install: The majority of users who installed a Street Performance or Torque cam reported no valvetrain failures, no abnormal wear on cam lobes, and no loss of oil pressure after 20,000–40,000 miles. Many owners drive 10,000–15,000 miles per year with regular oil changes and have not experienced any cam-related problems.
  • Valve spring longevity: Crower supplies matched valve springs designed for their cam profiles. Users who replaced springs as part of the kit (rather than reusing factory springs) saw zero spring failures. This aligns with manufacturer recommendations: using the correct spring kit is critical for reliability.
  • Idle quality and drivability: Even with Stage 2 and Stage 3 cams, owners reported that the engines remained street-friendly after proper tuning. Cold starts, daily traffic, and highway cruising were manageable, though idle was noticeably choppier on more aggressive grinds.
  • No premature lifter failure: Factory HEMI lifters (MDS or non-MDS) are often a weak point when paired with high-lift cams. However, users who installed Crower cams with the supplied Crower lifters or other high-quality aftermarket lifters (such as Johnson or Morel) reported no lifter failures. Those who attempted to reuse high-mileage factory lifters sometimes experienced ticking or collapse after aggressive cam installation.

Common Concerns and How Crower Addresses Them

  • Increased valvetrain noise: A typical trade-off with aftermarket cams is louder valve clatter from higher spring pressures and more aggressive ramps. Crower uses smooth lobe profiles to minimize noise compared to some competitors. Proper lash adjustment (if using mechanical lifters) or correct lifter preload (hydro-mechanical) keeps noise in check.
  • Potential for valve float at high RPM: Crower’s race cams are designed to work with dual springs or high-rate single springs to control the valve at RPMs exceeding 6500. Users who matched spring pressures to cam specs reported no floating or valve bounce even during sustained high-RPM pulls.
  • Need for a custom tune: Every cam upgrade requires recalibrating the ECU. Plug-and-play tuners like HP Tuners or DiabloSport are used to adjust fuel tables, ignition timing, idle speed, and VVT phasing. Without a proper tune, the engine may run lean, have poor driveability, or even suffer engine damage. Crower provides baseline cam timing data for common grinds, but a dyno tune is strongly recommended.

Installation Best Practices for Maximum Long-Term Reliability

Installing a camshaft in a pushrod V8 like the 6.4 HEMI is a major job that requires mechanical skill and attention to detail. Even the best components will fail if installation is sloppy. Here are critical tips from Crower and seasoned builders to ensure your upgrade lasts for years:

Replace All Valvetrain Components as a Set

Do not mix and match old and new parts. Use a complete Crower cam kit that includes the camshaft, lifters, pushrods, valve springs, retainers, and locks. Mixing wear patterns between old and new components can cause premature failure. Crower’s kits are engineered to work together harmoniously.

Check Piston-to-Valve Clearance

Aggressive cam profiles may cause valves to contact pistons, especially if the engine has been milled heads or a thin head gasket. Always clay-check clearance when installing a Race or custom-grind cam. Crower provides clearance specifications for each cam grind. If clearance is insufficient, either choose a less aggressive cam or machine reliefs into the pistons.

Proper Break-In Procedure

Flat-tappet cams require a break-in procedure with specific engine oil and additives (such as ZDDP). However, the 6.4 HEMI uses roller lifters on the cam lobes, which are much less prone to wear. Still, break-in is critical for the lifters’ inner plunger and pushrod cup. Follow the manufacturer’s instructions: run the engine at 2000–2500 RPM for 20 minutes using a high-zinc break-in oil, then check valve lash after cool-down. Crower recommends their own break-in oil or a reputable synthetic blend with high anti-wear additives.

Torque Specifications and Timing Chain Tension

Always use a new timing chain, tensioner, and guides. The 6.4 HEMI is sensitive to timing chain stretch. Crower specifies that cam bolts be torqued to 25 ft-lbs plus 90 degrees, and the camshaft retainer bolts to 105 in-lbs. Use a torque wrench and follow factory service manual procedures. After installation, rotate the engine by hand several times to ensure no binding occurs.

Professional Installation for Complex Builds

While many enthusiasts install cams themselves, owners who are not fully comfortable with engine internals should invest in a professional installation. A trusted performance shop with HEMI experience can ensure perfect cam timing, correct lifter preload, and proper valvetrain geometry. This investment pays for itself in long-term reliability. Several Crower dealers offer installation services and can provide a dyno tune immediately after the cam swap.

Comparison: Crower vs. Other Aftermarket Camshafts for the 6.4 HEMI

It’s always helpful to see how Crower stacks up against competitors like Comp Cams, Lunati, and Melling. Here is a high-level comparison based on reliability and performance:

  • Crower – Billet steel construction, smooth lobe designs, matched valvetrain kits. Excellent for street and mild race applications. Backed by a lifetime warranty. Slightly higher price point but justified by reliability.
  • Comp Cams – Offers aggressive lobe profiles that can produce top power numbers, but some users report higher valvetrain noise and occasional lifter failures on HEMI engines if not paired with proper springs. More economical options available.
  • Lunati – Known for budget-friendly cams, but quality control can be inconsistent. Some builders prefer Lunati for drag-only builds where occasional maintenance is acceptable.
  • Melling – OEM OEM-focused but offers some performance grinds. Limited aggressive profiles; more suitable for mild street upgrades.

For maximum long-term reliability with street-driven vehicles, Crower stands out due to its comprehensive testing and matched component approach. Many high-mileage 6.4 HEMI builds on LXForums and Mopar boards specifically cite Crower as their top recommendation for dependable daily-driver cam swaps.

Real-World Build Example: 6.4 HEMI with Crower Stage 2 Street Cam

To illustrate real-world reliability, here is a documented build from a 2018 Dodge Charger Scat Pack with 30,000 miles. The owner installed a Crower Street Performance cam (p/n 47397) along with Crower valve springs, retainers, and pushrods. The vehicle was tuned by a local shop using HP Tuners, targeting 93 octane fuel. After 20,000 miles, the owner reported:

  • Dyno-proven gain of 65 wheel horsepower and 40 lb-ft of torque.
  • No engine oil consumption increase.
  • Idle is slightly choppy but acceptable for daily commuting.
  • Cold starts in winter (temps down to 10°F) are reliable with proper tuning.
  • No lifter tick or valvetrain noise beyond normal.

This owner’s positive outcome reflects the broader trend: a properly installed Crower cam upgrade with matching components and a quality tune will deliver many trouble-free miles.

Maintenance Considerations for Long-Term Health

Upgraded cams place additional stress on the valvetrain, so maintenance intervals should be tightened. Here are recommendations:

  • Oil changes every 3,000–5,000 miles with a high-quality synthetic 5W-30 or 5W-40 that meets ILSAC GF-6 or API SP standards. Avoid cheap conventional oils.
  • Inspect valve lash every 30,000 miles if using mechanical lifters. Hydraulic lifters rarely need adjustment, but checking pushrod wear is good practice.
  • Replace spark plugs at manufacturer interval but consider upgrading to a colder range if the engine is run hard often.
  • Monitor oil pressure with a gauge. Any significant drop could indicate bearing wear or lifter issues. Many aftermarket cam users install a mechanical oil pressure gauge for peace of mind.

Conclusion: Are Crower Cam Upgrades Worth the Investment for Long-Term Performance?

Based on extensive user feedback and engineering data, Crower camshafts for the 6.4 HEMI engine deliver reliable power increases when installed as part of a matched valvetrain system. The key to long-term reliability lies in three factors: using a complete Crower kit (not mixing parts), performing a careful installation with proper break-in and tuning, and following a rigorous maintenance schedule. Owners who adhere to these guidelines report satisfaction even after 40,000+ miles of mixed driving.

For those seeking a balance of aggressive performance and everyday dependability, the Crower Street Performance or Torque cam lines are excellent choices. Track-focused builders will benefit from Crower’s Race cams, but must accept the trade-offs in drivability and the need for more frequent inspections. Finally, always consult with a professional tuner and, if possible, a certified Crower dealer to ensure your specific engine configuration is optimized.

External resources for further reading: Crower Official Website | LXForums 6.4 HEMI Performance Section | HP Tuners for ECM Calibration