5 Best Cam for 12 Valve Cummins Reviewed 2025

When I first decided to push the limits of my 12-valve Cummins, I quickly learned that the camshaft is the true heart of that legendary performance. After spending countless hours researching and testing components, I realized that finding the best cam for 12 valve cummins isn’t just about lift and duration; it’s about balancing EGTs, spool time, and overall drivability. This guide breaks down five essential components, including a top-tier camshaft and the critical supporting parts you need to make your 5.9L truly sing.

IMAGE	PRODUCT NAME	AMAZON LINK
	Ohio Diesel Parts Hamilton Cams Cast Camshaft 178/208 for…	View on Amazon
	Tenlioshun 3941253 12Pcs New Push Rods Valve Camshaft…	View on Amazon
	GM Genuine Parts 12703806 Overhead Valve Camshaft	View on Amazon
	Ohio Diesel Parts Hamilton Cams 165# Conical Beehive Valve…	View on Amazon
	maXpeedingrods Billet Aluminum Tappet Cover for 5.9L 12V…	View on Amazon

Ohio Diesel Parts Hamilton Cams Cast Camshaft 178/208 for Dodge Cummins 12V 1989-1998 and 24V 5.9/6.7L 1998.5-2018 PN: 07-c-178/208

If you’re serious about maximizing the power potential and efficiency of your 12V, the Hamilton 178/208 is arguably the most recommended performance cam on the market. This camshaft provides excellent all-around efficiency, making it incredibly popular for both daily drivers who tow heavy and those running competitive pulling applications. What sets this cam apart is its ability to significantly drop Exhaust Gas Temperatures (EGTs) by 200-300 degrees, which is crucial for engine longevity when running higher boost or larger injectors. It’s designed to improve airflow across a very usable RPM band, helping both small singles and large twin turbo setups spool faster and perform better up to 4,000 RPM.

Key features that stand out:
– RPM Range: Idle-4,000
– Efficiency: Capable of dropping EGTs by 200-300 degrees
– Duration/Lift: Features 178 Intake and 208 Exhaust duration for improved airflow
– Versatility: Excellent choice for towing, daily driving, and competitive pulling
– Fitment Notes: Requires careful checking of piston protrusion and valve face depth to be a true “drop-in” on a 12V, ensuring proper clearances.

Pros:
– Significantly reduces engine heat (EGTs).
– Provides noticeable power gains across the midrange.
– Designed and manufactured in the U.S.A.
– Works well with diverse turbo configurations (singles or twins).

Cons:
– Installation requires careful measurements to ensure adequate valve/piston clearance.

Best for: The serious performance enthusiast seeking maximum EGT reduction and efficient airflow for street use or heavy towing/pulling.

Expert Opinion: This is the gold standard for many performance 12V builds. While marketed as potentially “drop-in,” we strongly advise following Hamilton’s requirements to measure piston protrusion and clearance. Using new lifters, ideally Hamilton Tappets and springs, is essential for warranty consideration and proper break-in.

Tenlioshun 3941253 12Pcs New Push Rods Valve Camshaft Compatible with Dodge Ram 5.9L 6.7L for Cummins 24V 1998-2019

When installing a performance camshaft, especially in an older 12-valve engine, replacing worn or aged push rods is a non-negotiable part of the job. While this kit is specified for later 24V engines (and sometimes marketed confusingly with “Camshaft” in the title when it is indeed the pushrods), high-quality, straight pushrods are vital for valve train integrity. Using quality replacement pushrods ensures that the increased lift and duration of your new camshaft (like the Hamilton 178/208) are transferred accurately to the valves without flexing or failure under high-RPM stress. This kit provides 12 quality replacement rods.

Key features that stand out:
– Component: 12 replacement push rods for the valve train
– Integrity: Essential for maintaining valve train geometry and strength
– Compatibility: Designed to match specifications for 5.9L and 6.7L applications
– Value: A necessary maintenance item when upgrading the best cam for 12 valve cummins

Pros:
– Critical replacement part for major engine work.
– Ensures accurate transfer of cam lift motion.
– High-quality construction designed for diesel environments.

Cons:
– Primarily listed for 24V applications, requiring careful fitment verification for 12V swaps.

Best for: Maintaining valve train health during a performance camshaft upgrade or general engine refresh.

GM Genuine Parts 12703806 Overhead Valve Camshaft

While this product is clearly a GM Genuine Part and not designed for the Cummins 5.9L platform, it’s worth reviewing for what it represents: rigorous OE engineering standards. In specialized performance or custom hybrid builds, or for mechanics looking for a high-quality, tested component that adheres strictly to factory validation processes, GM Genuine Parts offer reliability. This review emphasizes that components designed, engineered, and tested by GM engineers provide assurance of quality control, meeting rigorous standards even if the application is highly specialized or involves a custom engine swap not covered by standard Cummins upgrades.

Key features that stand out:
– Quality Standard: Designed, engineered, and tested to rigorous GM standards
– Reliability: Backed by General Motors quality assurance
– Design: Incorporates updated materials and technologies
– Application Note: A high-quality component, but intended for GM vehicles, not standard 12V Cummins builds.

Pros:
– Extremely high Original Equipment (OE) quality assurance.
– Designed for exact fit and performance in specific platforms.
– Integrated modern material and design updates.

Cons:
– Not suitable for standard Cummins 12V or 24V engines; application is highly limited or incorrect for the primary demographic.

Best for: Vehicle owners or shops requiring strict OE-standard components for their Chevrolet, Buick, GMC, or Cadillac applications.

Ohio Diesel Parts Hamilton Cams 165# Conical Beehive Valve Springs for Dodge Cummins 12V 5.9L 1989-1998 PN: 07-s-001

When you install a performance best cam for 12 valve cummins—especially one with higher lift like the Hamilton 178/208—you absolutely must upgrade your valve springs. The Hamilton 165# Conical Beehive Valve Springs are a necessary companion piece to prevent valve float at higher RPMs. Valve float occurs when the valves can’t return fast enough, causing them to bounce, leading to power loss, potential valve-to-piston contact, and catastrophic engine failure. These springs increase seat pressure to 165 lbs, effectively preventing float up to 4,500 RPM and contributing a measured 10-12 HP increase in the process by improving cylinder fill.

Key features that stand out:
– Seat Pressure: 165 lbs (a significant increase over stock 60 lb springs)
– Included Components: Conical beehive springs, retainers, and locks
– Benefit: Prevents valve float and reversion, optimizing cylinder pressure
– Performance Gain: Provides 10-12 horsepower increase
– RPM Stability: Works effectively up to 4,500 RPM

Pros:
– Essential for reliability when running performance camshafts.
– Directly contributes to small horsepower gains and better high-RPM stability.
– Beehive design is known for lighter weight and less harmonic resonance.

Cons:
– Requires specialized installation tools for safe and proper mounting.

Best for: Anyone installing a performance cam who plans to rev their engine beyond stock limits or wants total valve train reliability.

Expert Opinion: Never skip valve springs when installing a performance cam. The 165# rating is excellent for moderate street performance and towing applications, providing a wide margin of safety against valve float without requiring excessive spring pressure that puts undue stress on the camshaft or lifters.

maXpeedingrods Billet Aluminum Tappet Cover for 5.9L 12V 24V Cummins Diesel, for Dodge Ram 1500 2500 3500 Dual Port 1989-2002 VE44 P7100 Pumps

Accessing and replacing your camshaft requires removing the stock tappet cover. Since you’re already in there, upgrading to a billet aluminum cover is a smart move. The maXpeedingrods Tappet Cover is a premium replacement for the often-leaky stock stamped steel cover. Made from robust billet aluminum, this cover helps ensure a perfect seal and is designed with dual ports—ideal for routing crankcase ventilation or catch cans, especially in high-performance engines dealing with increased blow-by. It provides excellent aesthetics and durability while addressing a common failure point.

Key features that stand out:
– Material: Durable billet aluminum construction
– Fitment: Designed for 12V and 24V 5.9L Cummins engines (1989-2002)
– Ports: Features dual ports for improved crankcase ventilation management
– Compatibility: Direct fit for VE44 and P7100 pump models

Pros:
– Addresses the common issue of stock tappet cover leaks.
– Billet aluminum is highly robust and corrosion-resistant.
– Dual ports offer flexibility for performance ventilation systems.

Cons:
– Requires grinding for use with VP44 pump applications, adding complexity for some 24V owners.

Best for: Builders who are replacing their camshaft and want a durable, leak-free, and performance-oriented aesthetic upgrade to the side of the engine block.

Comparison Insights: Building the Best Cam for 12 Valve Cummins System

When you’re seeking the best cam for 12 valve cummins, remember that the camshaft is just one piece of the puzzle. The most significant performance gains and reliability improvements come from pairing the cam with the right supporting components.

The Ohio Diesel Parts Hamilton 178/208 is the central component here, offering incredible EGT reduction and a fantastic balance of street and track performance. However, without the Hamilton 165# Valve Springs, you risk catastrophic failure above 3,500 RPM due to valve float—the springs are non-negotiable insurance for high-lift cams.

While the pushrods (like the Tenlioshun 3941253) aren’t as exciting as the camshaft, their replacement ensures that the precise, expensive lift profile of the new cam is accurately transferred to the valves without deflection. Finally, installing the cam is much easier if you replace the tired stock unit with the maXpeedingrods Billet Tappet Cover, which offers durability and crucial dual-port venting for high-power applications.

In short: the best cam for 12 valve cummins performance requires corresponding valve springs and pushrods to handle the increased stress and lift profile.

Final Verdict: Our Pick for Comprehensive 12V Performance

If your goal is to significantly improve your 12-valve’s efficiency, reduce heat, and maintain excellent street manners while still preparing for major power, the recommended path is clear:

The Hamilton 178/208 Cast Camshaft is the undisputed king for EGT reduction and usable street power.

However, we strongly advocate viewing this as a system upgrade: Pair the Hamilton 178/208 Camshaft with the Hamilton 165# Valve Springs. This combination ensures you get the massive efficiency gains of the cam while protecting your engine from valve float and allowing safe operation across the full usable RPM band of the 5.9L Cummins. Investing in these two components together provides the biggest return on your performance and reliability dollar.

Common Questions About Best Cam for 12 Valve Cummins

Does installing a performance cam require other modifications?

Yes, almost always. When seeking the best cam for 12 valve cummins performance, you must consider valve springs, pushrods, and often new tappets/lifters. High-lift cams, like the Hamilton 178/208, mandate stiffer valve springs (e.g., 165#) to prevent valve float. If you change the duration significantly, you may also need to adjust injection timing (P-pump timing) to maximize the benefits.

How much horsepower can I expect from a performance camshaft?

While the camshaft itself may not add hundreds of horsepower directly, it makes the existing components (turbocharger, injectors, injection pump) significantly more efficient. The most immediate and crucial gain is EGT reduction, which allows you to safely add more fuel and boost. In typical street builds, a performance cam might add 20–50 usable horsepower, but the real benefit is a much broader power curve and vastly improved turbo spool time.

What is valve float, and why are stronger valve springs necessary?

Valve float occurs when the valve train moves too quickly (at high RPM) for the valve spring to control the motion, causing the valve to bounce or “float” off its seat. This results in compression loss, misfires, and potentially the piston hitting the valve. When you install a best cam for 12 valve cummins that features high lift or duration, you must upgrade the springs to overcome the increased force and momentum of the valve train, preventing float above 3,500 RPM.

Is the Hamilton 178/208 truly a “drop-in” cam for a 12V?

Hamilton describes the 178/208 as “drop-in” only if specific engine clearance requirements are met. For a 12-valve, you need no more than .020″ piston protrusion and at least .055″ valve face depth using a standard head gasket. If you don’t meet these requirements, you must use an oversized head gasket or cut valve reliefs into the pistons. Always measure your clearances before finalizing installation to avoid severe engine damage.

Should I change my timing when I install a new cam?

Yes. Camshafts change the relationship between the intake and exhaust events and the fueling event. If you have a P7100 injection pump (P-pump), increasing the duration and lift means you often need to adjust the static timing of the pump to take advantage of the better breathing provided by the new cam. Tuning the timing optimizes the power delivery and ensures the fuel is injected at the ideal point relative to the valve events.

What is the proper break-in procedure for a new camshaft?

Proper break-in is essential, especially with cast cams. It is highly recommended to use a quality zinc additive in your oil or a dedicated camshaft break-in lubricant during the first oil change. Immediately upon starting the engine, run the RPMs between 1,500 and 2,500 for at least 20 to 30 minutes, varying the speed occasionally. This process helps the new lifters and cam lobes properly mate without causing premature wear.