Choosing the Right Pushrod for Different Racing Applications

Racing is all about performance–every part of a high-revving engine works together to achieve the perfect balance of speed, reliability, and efficiency. But one component that often flies under the radar is the unassuming pushrod. And that’s not really fair, is it? After all, this is a critical piece of the valvetrain, responsible for maintaining stability as well as overall engine function.

Whether you’re screaming down the drag strip, tearing around a circle track, or grinding through a grueling road race, the right pushrod can mean the difference between a trip to the winner’s circle and a DNF. But upgrading isn’t as simple as just picking out whatever fits–different types of racing place unique demands on valvetrain components, and factors like pushrod material, wall thickness, diameter, and length all affect how these parts perform.

With that in mind, let’s break down what to look for in pushrods across different racing disciplines and help you find the best fit for your build.

The Evolution of The Modern Pushrod

Before getting into parts selection, it’s worth reviewing what pushrods do and how they’ve evolved. Simply put, pushrods connect the camshaft to the valvetrain, transferring motion from the lifters to the rocker arms, which then open and close the valves. Most modern pushrods have either ball or cup-style ends, although specific designs vary by application. While under load, pushrods endure significant vibration and shock from the valve springs. This isn’t a problem in stock engines, but as cam profiles get more aggressive, stronger valve springs are needed to handle higher RPMs, which puts added stress on the rods.

A pushrod’s strength really comes down to its resistance to bending, or column stiffness. During early testing, Trend Performance founder Bob Fox and Hendrick Motorsports’ Randy Dorton discovered that conventional 5/16” pushrods were flexing under load, which threw off valve timing. They also found that lifters were momentarily losing contact with the camshaft, causing power loss–a phenomenon known as tappet lofting.

That all changed in 1993, however, with the invention of the Spintron, a revolutionary machine that simulates engine operation and uses lasers to precisely measure valve movement. Finally, with real data in hand, pushrod companies could refine designs to create thicker, more durable pushrods with far better valve control. It took some time for racers to fully accept the extra mass, but they eventually shifted from 5/16” pushrods to 7/16” or even 9/16”, recognizing that stiffness (as opposed to weight) was more important for reliability and power.

Key Considerations for Pushrod Selection

Material Makeup

Most modern performance engines use pushrods made from high-strength materials like chromoly steel, tool steel, or titanium, all of which come with their own advantages and trade-offs. Chromoly steel alloys–typically 4130, 4135, or 4340–are popular choices for their excellent strength-to-weight ratio and durability. For more extreme applications like Top Fuel, Funny Car, Pro Mod, and truck and tractor pulling, solid tool steel, like H13, has nearly three times the tensile strength of 4130, but with similar elasticity. Then there’s the more-expensive titanium, which is lighter and may be preferred for some high-RPM applications where cutting weight is a bigger priority. Manufacturers will often add surface finishes, like black oxide coating or nitriding, to further reduce wear and friction between the pushrod tips and rocker arms.

Wall Thickness & Diameter

A pushrod’s diameter and wall thickness play an important role in performance and valvetrain stability, particularly in racing engines. A larger diameter adds stiffness by spreading out the load and maintaining stability at high RPMs. Thicker walls add even more strength and durability, making them ideal for engines with high spring pressures or power adders. Stiffer pushrods naturally resist deflection better, which helps maintain net lift at the valve while improving airflow, maximizing power, and ensuring proper valve timing. Of course, there are trade-offs–namely clearance issues and added weight. But tapered designs often help balance strength with space limitations. And in most cases, the benefits of stronger pushrods far outweigh any concerns about extra mass.

Pushrod Length

Proper valvetrain geometry depends on getting pushrod length just right. If it’s too short or too long, it can throw off the valve timing, put excess wear on lifters and rocker arms, and ultimately restrict engine performance. Ideally, the rocker tip should move as little as possible across the center of the valve tip to reduce friction and side loading, which is especially important in high-RPM applications. The best way to figure out the correct length is by using an adjustable pushrod length checker during mock-up. While this is a meticulous process that often takes some trial and error, it’s worth it to make sure the pushrod delivers the right preload on hydraulic lifters or the correct lash for solid lifter setups.

Pushrod Demands for Different Racing Applications

Drag Racing

Pushrods in drag racing engines need to be incredibly strong and rigid to handle short bursts of extreme RPM and high valve spring pressures. We’re talking about massive loads–in the neighborhood of 240,000 pounds at high RPM–where even the slightest flex or deflection can lead to valve float, power loss, or even engine damage.

Material choice is a big factor here. High-strength options like 4130 chromoly are solid choices, while top-tier classes often use H13 or S7 tool steel for their superior resistance to fatigue cracking from constant heat cycles. When it comes to design, bigger is almost always better. A larger diameter spreads the load over a wider area, making the pushrod stronger and stiffer. Thicker walls help, too; that’s why heavy-wall pushrods are common in engines running high spring pressures or power adders like nitrous and boost.

Length depends on the engine configuration, but shorter pushrods have the advantage of being stiffer and lighter. For additional strength in extreme applications like Top Fuel and Funny Car engines, some builders prefer solid pushrods machined from bar stock instead of hollow tubes. And, while weight is a concern on the valve side of the valvetrain, it’s less of an issue for pushrods since they operate on the slower-moving side.

Circle Track Competition

Circle track racing pushes engines to their limits with sustained high RPM over (obviously) much longer distances than drag racing. In these applications, pushrods need to strike the right balance between stiffness, weight, and durability to handle unique demands.

Running at elevated RPM for extended periods puts constant stress on the valvetrain, making pushrod selection critical. They need to be stiff enough to maintain stability but light enough to minimize rotational mass. Dialing in the diameter and wall thickness is key to overall rigidity. For example, a 3/8″ pushrod with a 0.080″ wall is about twice as stiff as a 5/16″ pushrod with the same wall thickness, which significantly improves valvetrain stability at high RPMs. Meanwhile, increasing a 3/8″ pushrod’s wall thickness from 0.080″ to 0.135″ raises its stiffness by 122% compared to a 5/16″ pushrod with a 0.080″ wall.

Chromoly (4130 steel) pushrods with moderate wall thickness often provide the ideal combination of strength and weight. With races that can last hundreds of laps, durability is a top priority–another reason why 4130 chromoly is a go-to material for its toughness and fatigue resistance.

Circle track engines also run cam profiles tuned to specific track demands, whether it’s a short track, speedway, or superspeedway. When choosing pushrods, factors like cam profile, track banking, and g-forces can all contribute to valvetrain stability.

Endurance Racing

Whether it’s road racing, off-road competition, or a twin Big Block Chevy engine boat soaring through the air, endurance racing calls for reliability and longevity. These engines must perform over long distances, often in brutal conditions, meaning pushrods need to handle heat, fatigue, and wear while keeping the valvetrain stable.   

With races lasting for hours, engines are exposed to sustained high temperatures. Pushrods have to manage this heat without sacrificing toughness, so chromoly steel is a popular choice here as well. Its heat resistance and durability make it well-suited for a range of endurance applications. H13 tool steel, with its impressive tensile strength, is another option for these engines. While lightweight alloys like titanium might seem appealing, they tend to struggle over long races.

Once again, stiffer pushrods are more resistant to bending or energy buildup over extended periods, both of which can lead to valve timing issues and even potential engine damage. A shorter length (depending on the engine setup, of course), larger diameter (at least 5/16”), and thicker wall (.120”) all add stiffness and deliver reliable performance.

Proper lubrication also affects longevity. Pushrods with integrated oiling channels or special coatings like DLC (Diamond-Like Carbon) help keep parts lubricated over long runs, which reduces wear and lowers the risk of failure.

Compatibility with Other Components

A pushrod doesn’t operate in a vacuum; it has to work seamlessly with other valvetrain components. Which means the type of lifter in your engine will influence pushrod selection. Hydraulic lifters need the right preload for quiet operation and longevity, while solid lifters require precise pushrod length to maintain proper valve lash. If the pushrod length doesn’t match the lifter type, you could end up with excessive wear and performance left in the garage.

Rocker arm ratios also impact pushrod loading. A higher rocker ratio increases valve lift and puts more stress on the pushrods, so they need to be stronger and stiffer. In high-lift cam setups, pushrods with reinforced walls and high-quality materials can help manage the added force.

Aggressive camshafts and high spring pressures put additional load on the pushrods. In engines with extreme valve spring pressures, using pushrods with a larger diameter and stronger materials helps prevent deflection for better reliability.

Custom vs. Off-the-Shelf

For many racers, the decision between custom and off-the-shelf pushrods depends on the specific needs of the build. Off-the-shelf pushrods are readily available and cost-effective, making them a solid choice for common racing applications. However, custom pushrods let you choose the specific materials, lengths, diameters, and wall thicknesses for your combination. They may be better suited for unique setups that require an exact fit for precise valvetrain geometry, although they do come with a higher price tag and longer lead times.

Pushrods that Drive Performance

They might look like simple metal tubes, but pushrods should never be underestimated. Handling thousands of pounds of pressure at high frequencies, these critical components help maintain valvetrain stability and keep your engine running at peak efficiency.

Choosing the right pushrod means understanding which characteristics best match your setup and the type of racing you do. Whether the road ahead is a straight line, an oval, or a course with twists, turns, and elevation changes, the ideal pushrod will deliver the perfect balance of stiffness, strength, and durability.

For your next build, Manley Performance offers a massive catalog of top-quality, one-piece pushrods, precision-crafted from high-strength 4130 chromoly. Options include standard .080″ wall pushrods in 5/16″ and 3/8″ diameters, as well as beefier .120″ wall versions in the same sizes. For maximum strength, Manley’s 7/16″ pushrods with a rugged .165″ wall are an excellent choice. With lengths ranging from 6 to 11 inches, Manley has a pushrod for virtually any engine configuration. For more information, visit manleyperformance.com.