The History of Stage V Rocker Arms
For more than four decades, the Stage V name has been closely connected with Chrysler Hemi performance. From early Top Fuel engines to modern street and race builds, Stage V components earned their reputation by solving some of the Hemi valvetrain’s most difficult problems. The company’s rocker arms were not developed merely as replacements for factory parts. They were created to improve strength, geometry, durability, and serviceability in applications where valvetrain reliability was critical.
Today, Manton Racing Products is proud to continue the production and service of the Stage V rocker-arm line. To understand why these rocker arms remain important, it is helpful to look back at the racing environment in which Stage V Engineering was founded and the engineering challenges its founders set out to solve.
The Beginning of Stage V Engineering
Stage V Engineering was founded by Eric Hansen and Bill Stel in the summer of 1984. The company entered the industry at a time when the Chrysler Hemi had already proven itself as one of the most capable racing-engine designs ever produced. However, original Hemi parts were becoming increasingly scarce and expensive, while racers continued to demand more power and reliability from the platform.
Stage V initially became known for its Hemi cylinder heads. Beginning with Joe Schubeck’s earlier Stage II cylinder-head patterns, Hansen and Stel extensively revised the design and developed the water-jacketed Stage V Top Fuel head. These heads quickly established Stage V among serious racers.
One of the company’s early milestones came when Larry Minor reportedly ran a 5.43-second elapsed time at the NHRA Winternationals using Stage V heads. At the time, it was the quickest elapsed time recorded in Top Fuel. Stage V components would eventually be used by prominent racers and teams such as Frank Bradley, Tom McEwen, Blue Max, Dale Pulde, and Al Teague’s record-setting Bonneville streamliner.
This racing experience shaped the company’s approach to rocker-arm design. The extreme conditions found in Top Fuel exposed weaknesses that might never appear in a typical street engine. Stage V’s rocker arms were developed in an environment where reducing weight could not come at the expense of strength, and where every component needed to remain dependable under severe loading.
Rocker Arms as an Engineering Solution
Stage V’s rocker arms became especially important during the development of the company’s Hemi conversion cylinder heads.
Although the Chrysler 426 Hemi and the Chrysler B and RB wedge engines shared the same basic bore spacing and several major dimensions, a Hemi cylinder head could not simply be bolted onto a production wedge block. One of the most significant obstacles was the pushrod arrangement.
The production Hemi block incorporated deep channels in the valley to provide clearance for the Hemi’s outward-canted pushrods. The more common wedge block did not have these channels. While some material could be removed from a wedge block for additional clearance, the pushrods still needed to remain in a relatively straight row.
Stage V addressed this problem through the cylinder head and rocker-arm geometry. The exhaust rocker arm was lengthened, and its rocker shaft was raised. This allowed the pushrod location to be changed while retaining the intended rocker ratio and valve-side geometry.
The pushrod ends of certain intake and exhaust rocker arms also had to be repositioned. Altogether, the conversion required four different rocker-arm castings.
These purpose-built rocker arms were essential to the Stage V Hemi conversion. They allowed Hemi-style cylinder heads to be used on readily available Chrysler 413 and 440 RB blocks, opening the door to Hemi performance without requiring an increasingly rare original 426 Hemi block.
The result demonstrated an important part of the Stage V philosophy: rocker arms should be designed as part of the complete valvetrain system. Rocker length, shaft position, pushrod location, valve position, ratio, oil delivery, and component stiffness all had to work together.
The Development of a Purpose-Built Rocker Arm
Stage V rocker arms were developed specifically for the demands of high-performance Hemi engines. Rather than simply reproducing the factory design, Stage V created rocker arms that could support the company’s cylinder-head conversions and the increasingly demanding requirements of racing engines.
Their design emphasized strength, reduced weight, serviceability, and compatibility with different Hemi applications. These qualities helped the rocker arms move beyond the original conversion program and become a respected option for both racing and street-based performance engines.
The rocker arms also reflected Stage V’s broader approach to manufacturing. The company focused on producing specialized components in-house and supporting them over the long term. That commitment became an important part of the product’s identity.
Roller-Tip Development
One of Stage V’s most important contributions to the Hemi valvetrain was its early use of roller-tip rocker arms.
Factory Hemi rocker arms used a sliding contact pad at the valve tip. Stage V introduced a roller-tip design that reduced sliding friction and helped control contact between the rocker and valve. This was especially valuable in racing engines using high spring pressure and aggressive camshaft profiles.
The roller-tip rocker arms helped reduce wear and became a defining feature of the Stage V design. Their use across street, competition, alcohol, and Top Fuel applications helped establish Stage V as a pioneer in bringing roller technology to the Hemi valvetrain.
The roller assemblies were also designed to be serviceable. If a roller or related component became worn or damaged, the rocker could be rebuilt instead of being discarded. This was particularly valuable in racing applications, where valvetrain components were exposed to extreme operating conditions.
Serviceability and Long-Term Use
Stage V rocker arms were designed with long-term service in mind. Replaceable bushings, rollers, pins, adjusters, and related components allowed the rocker systems to be maintained and rebuilt as needed.
That approach was important to racers and engine builders who had invested heavily in their combinations. Instead of treating a worn rocker arm as a disposable part, Stage V provided a path for continued use.
Many Stage V rocker systems have remained in service for decades. Their ability to be repaired and supported has helped preserve the product line and maintain its place in the Hemi performance community.
Development for Different Applications
As the Stage V line developed, it expanded beyond a single intake and exhaust rocker configuration.
Different rocker ratios were offered for applications requiring additional valve lift, while various rocker lengths and adjuster sizes allowed the design to be adapted to different engine combinations.
Stage V also developed specialized severe-duty and Top Fuel exhaust rockers. These products were created for the increasingly demanding conditions found in supercharged alcohol and fuel racing.
Over time, different rocker ratios, lengths, adjuster sizes, pushrod locations, and oiling arrangements allowed the Stage V design to serve traditional 426 Hemis, Hemi conversion engines, bracket-racing combinations, Nostalgia Super Stock engines, supercharged alcohol engines, and Top Fuel applications.
This broad range of applications helped Stage V rocker arms become familiar to generations of Hemi engine builders.
A Recognizable Stage V Design
In addition to their mechanical features, Stage V rocker arms developed a distinctive appearance. Traditional versions used a gray sandblasted finish with polished beam surfaces. Depending on the generation, the Stage V name was either engraved into or raised on the rocker body and highlighted.
That appearance became familiar to generations of Hemi engine builders. For many customers, the Stage V rocker was a component that combined purpose-built racing engineering with the craftsmanship of a specialty American manufacturer.
More importantly, the rocker arms were designed to be used, serviced, and rebuilt. Their value came not only from their performance, but also from the support and history behind the product.
Preserving the Stage V Legacy
In December 2023, For Hemis Only announced its purchase of Stage V Engineering. The acquisition included a company with a long history of producing Hemi cylinder heads, rocker arms, valve covers, and related components for both street and racing applications.
The Stage V rocker-arm tooling and production were subsequently acquired by Manton Racing Products. Manton became the exclusive manufacturer of Stage V rocker arms, while For Hemis Only continued the Stage V cylinder-head side of the product line.
For Manton, continuing the Stage V rocker-arm line represents more than adding another product to its catalog. Stage V was a family-owned American manufacturer built around racing, problem-solving, and specialized valvetrain engineering. Preserving the product line also preserves the work and legacy of Eric Hansen and the people who helped establish the Stage V name.
Manton continues to produce and support Stage V rocker systems for a wide range of Hemi applications. The current product line combines the established Stage V rocker design with modern supporting components and application-specific valvetrain systems.
Manton also continues to service existing Stage V rocker arms. This is especially important because many of these components have been in operation for decades. Replacement parts and rebuilding services allow older Stage V systems to remain in service rather than becoming obsolete.
Continuing the Story
The history of Stage V rocker arms is inseparable from the history of Chrysler Hemi racing. The company began by addressing the needs of serious Top Fuel racers, then applied that experience to Hemi conversion engines, street Hemis, bracket-racing combinations, and other demanding applications.
Stage V helped demonstrate that the rocker arm could be more than a replacement for the factory component. Through its Hemi conversion work, the company showed how rocker-arm geometry could help make new engine combinations possible. Through its early adoption of roller tips, Stage V helped bring reduced-friction valvetrain technology to the Hemi platform. Through its serviceable designs, the company created products that could remain useful for many years.
Most importantly, Stage V rocker arms were designed as parts of a complete valvetrain rather than isolated components. That systems-based approach remains central to Manton’s rocker-arm philosophy today.
By bringing Stage V rocker-arm production into the Manton family, we are working to ensure that these historic components remain available, serviceable, and relevant. The product may continue to evolve, but the objective remains the same: preserve the Stage V legacy while providing Hemi engine builders with rocker arms capable of meeting the demands of modern performance.
See our current Stage V selection here.