This extract from the Art of Balancing Article appeared in the National Dragster Magazine’s 14th issue of 2019 (2nd August 2019) and is reprinted with the permission of the NHRA.

There are three major types of balancers: elastomer, fluid, and friction. The elastomer type uses a rubber material, which controls much of the vibration. Viscous or fluid type uses fluid to absorb the flexing energy. Lastly, friction-style dampers rely on internal clutch discs to quell harmonics. “High-performance balancers are necessary to prolong the life of your engine,” said Nick Orefice, of Fluidampr. “You need a damper that will perform like it should in the most extreme conditions that stock dampers cannot do. Constantly changing and tuning race engines is what keeps teams competitive. With every change made, the harmonics of the engine change with it. A Fluidampr performance damper removes the guess work. It is engineered to protect over a wide band of frequencies throughout the entire rpm range, including high rpm. That means you can modify the engine and not worry if your harmonic balancer is properly tuned.”

Graham Withers, president/ owner of Pro/Race Performance Products, added, “Gas pressure in the combustion chamber has a direct relationship to the amplitude of the torsional vibration. Uncontrolled torsional vibration can damage and reduce the life of engine components. Examples could be rapid wear on the camshaft lifter lobes, stretching of the timing chain, grooving of the timing chain sprockets, through to causing the flywheel to come loose on the crankshaft. “Uncontrolled torsional vibration also robs an engine of valuable brake horsepower [BHP]. The differences between an OEM and a high-performance harmonic damper would be clearly seen on a dynamometer. Both the Pro/ Racer and Pro/Sport range of Dampers marketed by Pro/Race are SFI certified for competition and undergo annual testing for continued compliance

Withers also mentioned, “When building a race motor, the engine builder needs to consider the targeted rpm and BHP. An increase in gas pressure in the combustion chamber equals an increased twisting force on the crankshaft throws. This causes a deflection or twisting motion that is known as torsional vibration. The peaks of this back and forth motion are measured as amplitude. The function of the harmonic balancer is to reduce the amplitude of the torsional vibration peaks to an acceptable level. Most OEM harmonic dampers are not designed to cope with the rpm and BHP levels experienced in competition. That is why racers must consider a high-performance damper that is fit for purpose. For example, the SFI certified Pro/Racer dampers range have been spin tested to 18,000 rpm, well in excess of SFI requirements.”

Pro/Race markets three different streams of product: Pro/Street, Pro/Sport, and Pro/Racer. “For the high end of engine performance, our Pro/Racer harmonic balancers feature machined drive hub with a fine spline on the outer radius to couple to the inner surface of the elastomer dampening ring using a chemical bonding agent. The steel inertia ring is also machined with the fine spline to couple with the outer surface of the elastomer dampening ring, also using a chemical bonding agent. The effect of the spline is to nearly double the surface-area contact between the elastomer dampening ring and the hub and ring, thus eliminating any permanent rotational movement between the hub and the ring.

“The inertia ring is locked to the drive hub by a machined shoulder flange at the rear and a specially designed front flange, which is rolled closed over the drive hub to lock the inertia ring in place during final assembly of the damper. These design features are unique to Pro/Racer and have be proven out over decades of competition use.” The designer of the Pro/Racer dampers, and owner of Pro/Race Performance Products, Withers, was a professional drag racer and Australian champion. His years of practical experience with highperformance engines enabled him to develop effective harmonic dampers for a range of engine applications, which also meet or exceed the safety requirements of the SFI. A rearshoulder flange is machined into the inertia ring to provide containment of the inertia ring to the drive hub. The inertia ring has a specially designed front-enclosure flange, which is closed over the drive hub to lock in place the inertia ring.”

The PRO/RACER “All Steel” Harmonic Dampers are designed and manufactured for racing and high-performance street applications and are available for a wide range of engines. The PRO/RACER Damper is a direct replacement for the cast iron stock damper, which is no longer permitted by most racing sanctioning bodies due to the danger of fracture and high-speed disintegration or separation of the inertia ring from the hub. This problem is eliminated with a PRO/RACER Damper. The PRO/RACER “All Steel” Harmonic Damper is also a must for all belt-driven supercharger applications due to the additional torque loads on the damper hub and keyway, which results in failure in nearly 100% of all blower installations with a stock damper. Pro/ Racer now offers specific models for supercharged small-block (No. 74265), big-block Chevy (No. 74267), and small-block Ford (No. 74269) engines. These special dampers include dual keyways, and the Chevy versions also feature six tapped holes to accept most blower pulleys.

This specification is enforced by most racing sanctioning bodies to assure that the dampers conform to specified standards. While the SFI test is quite stringent and requires the damper to be spin tested at a speed of 12,000 rpm for a period of one hour, the PRO/RACER Damper has been tested at a speed of 18,000 rpm, substantially exceeding SFI requirements.

Harmonic dampers are supplied in two styles: those for internally balanced engines and those for externally balanced engines. Externally balanced engines have a counterweight bolted into the hub of the damper. The advantage of having a removable counterweight in the hub eliminates the possibility of having the counterweight mass move from its position. The PRO/RACER Damper for internally and externally balanced small-block and big-block Chevys and for small-block Chryslers are identical except for the counterweight. This means, for example, if you have a PRO/RACER Damper for a 400 small-block Chevy, you can remove the counterweight and the damper will work perfectly for a 350 Chevy. Conversely, if you have a 350 Damper and want to use it on a 400, you can now purchase the proper PRO/RACE counterweight and bolt it into your 350 Damper, and it is now a 400 Damper. All small-block Ford dampers are externally balanced with a counterweight. This counterweight can be removed for use on internally balanced engines.

PRO/RACE Performance Products will be exhibiting at the 32nd Annual Performance Racing Industry Trade Show in Indianapolis, December 12 – 14, 2019. Booth #343.

Every December is an exciting time for the PRO/RACE Team as we get to attend the PRI Trade Show, where we engage with our customers and distributors and interact with like-minded people all under the one roof.

If you are looking for a new Harmonic Damper to tame the vibration in your engine, a copy of our latest catalog or you’re just wanting some information from our experienced team with over 30+ years of manufacturing experience, then head on over to our booth this December at the 2019 trade show. Booth #343 Green Hall.

Whether you are a racer, engine builder; race crew member; fabricator or a distributor you don’t want to miss the three biggest business days in the racing industry.

If you’re attending the PRI Trade show this December, don’t forget to visit PRO/RACE Performance Products in the Green Hall – Booth #343.

National Title 50th Anniversary – Withers 200MPH Mangled Mess

Two cars line up, the engines rev and the crowd roars as Graham Withers enters the track tyres smokin’. In Ampol colours, Red, White and Blue, the GT-Rail Dragster in a spectacular wheel-stand entertain the mob as Withers, Australia’s first full-time Professional Drag Racer sets his sights on victory in his front engine 392 Chrysler Supercharged Hemi slingshot, which Withers designed and built himself. Withers seeking new sponsorship teamed up with Ampol and a legend was born.

‘It was Big Daddy Don Garlits, Florida, who was always at the leading edge of innovation in Top Fuel Drag Racing in the USA who influenced my driving. I had the will, drive and determination to be the best and challenge the norm’s’, says Wither.

The 3 November 2018 marks the 50th Anniversary of Withers three wins across 1966-67-68 making him a National Hero across Australia through the live television broadcasts at the time. There were no points system during the early years, it came down to the best driver on the day. Withers was the first Top Fuel driver to win the three events in consecutive years and this made him a legend at that time and created quite a stir. It is now 50 years since that historic moment at Calder Park Raceway.

When Keith Williams, the developer (Hamilton Island, Sea World etc.) offered appearance money to compete at his venue, Surfers Paradise International Raceway I knew Drag Racing was going to be more than just a hobby for me, says Withers.

Withers made the Sun newspapers front page after a miraculous escape while crashing at 200 mph at Calder Park Raceway. The accident was not his first or last incident; however other competitors were not happy with the domination of Withers, they sought for his removal. The Australian Hot Rod Federation established in 1966 (AHRF) intervened and sidelined Withers with no right of appeal. This situation would never happen today. A fierce competitor and dedicated engineer, it wasn’t long before he was back in his dragster to claim his three titles. Withers fondly remembers winning the first of his titles and describes it as his best experience.

The early days were frustrating as AHRF catered for both Show/Street and Drag Racing facets of the Sport. It was obvious Drag Racing was becoming a popular sport and required a new direction. Drag Racing set up their own organisation and Australian National Drag Racing Association (ANDRA) was formed in 1971.

I asked Withers if he did any other sports as a youngster, his reply, ‘no, as I wasn’t very sporty, so I built model aircraft and boats. However, my favourtie childhood race car driver was Circuit Racer Norm ‘Stormin Norman’ Beechey’.

After retiring from Top Fuel Drag Racing, Withers opened an automotive components parts business know as Graham Withers Speed Shop in 1972 where his many fans would stop by for a chat and advice. The shop in Cheltenham became Australia’s largest high-performance speed shop. Withers diversified into manufacturing where he designed, developed and patented his World-First High-Performance All-Steel Crankshaft Dampers.

Now 77, and with 95 per cent of PRO/RACE business in the USA, today Withers (President) sits at the helm of PRO/RACE Performance Products and continues to do business manufacturing and selling Dampers to Ford, General Motors and others in the USA and Australia. His range of Dampers includes PRO/STREET and SFI Spec-18.1 Certified PRO/RACER and PRO/SPORT.

Withers says, ‘If you have a passion for an activity, go for the challenge to be the best in your field’.


The Australian National Drag Racing Association would like to congratulate Graham Withers on his National Title 50 year anniversary. 














Written by Pauline Csuba MA(ProfWrit), Student, BA(ProfWrit/Journalism), Swinburne, DIP(PWE), CertIV(PWE), Box Hill Institute.
Writer/Freelance Journalist

Executive Personal Assistant to Mr Graham Withers.
Director- Graham Withers Charity Limited.

SEMA 2017 Pro Race












PRO/RACE Performance Products will be an exhibitor @
The 2017 SEMA SHOW in LAS VEGAS, NEVADA, USA from OCT 31 – NOV 3, 2017.

Come and visit our booth #73009 in The Racing Annex!

The SEMA Show is the premier automotive specialty products trade event in the world. It draws the industry’s brightest minds and hottest products to one place, the Las Vegas Convention Center. In addition, the SEMA Show provides attendees with educational seminars, product demonstrations, special events, networking opportunities and more.

SEMA Show Las Vegas 2017 Pro Race performance products








The 2016 SEMA Show drew more than 70,000 domestic and international buyers. The displays are segmented into 12 sections, and a “New Products Showcase” featured nearly 3,000 newly introduced parts, tools and components. In addition, the SEMA Show provides attendees with educational seminars, product demonstrations, special events, networking opportunities and more.

There will be a host of Celebrity Appearances which you can view here.

You can view the Floor Plan below or for a larger image please click here.

SEMA Show Las Vegas 2017 Pro Race performance products Floor Plan


Under Drive Damper by PRO/RACE ®.

Accessory drive systems have been made more compact on Late Model V8 engines like the Ford 4.6L and the GM LS1 by machining serpentine belt grooves on the OD of the crankshaft damper. The crankshaft damper functions as a combination crank damper and crank pulley on these engines.

Under drive dampers are smaller in diameter than stock production crank dampers which slows the speed of the accessories and reduces the HP required to drive them. Since performance and racing engine applications generally run at higher RPM, the water pump, alternator and power steering pump speeds can be reduced to save HP and still meet engine cooling, electrical and vehicle steering requirements.


  • High quality at an affordable price
  • Expertly made from premium materials
  • Built to match your exact requirements

The trick is to reduce the crank damper diameter without losing the torsion control capability required to prevent engine vibration and possible damage. The PRO/SPORT Under Drive dampers have been specially tuned to control crankshaft torsional vibration to stock production levels.

Dynamometer tests of the PRO/SPORT 25% under drive damper on a 2005 Mustang 4.6L 3V engine at Livernois Motorsports in Dearborn Heights, Michigan produced a 13 HP gain over a stock production damper.

#underdrivedampers #prorace

Each crankshaft has a natural frequency. If a crankshaft is held stationary at one end and a rotating load is applied to the other end, a twisting stress is created in the crankshaft. If the rotating load is released, the crankshaft springs back past its at-rest position and a twisting stress is briefly present  in the opposite direction.

The crankshaft again springs back past its at-rest position. This oscillation continues, in reducing amounts, until the crankshaft stops oscillating. The rate of the oscillation is referred to as the crankshaft’s natural frequency.

Torsional Vibration

In the engine, each power impulse imparts a torque, or rotating force to the crankshaft. Because one end of the crankshaft resists this rotation, full-power torque impulses can overcome the inherent stiffness of the crankshaft, causing it to twist. As the power pulse ceases, the crankshaft springs back in the opposite direction to “undo” the twist. It springs back past its at-rest position and a twisting stress or torsion is briefly present in the opposite direction.


The PRO/RACER “All Steel” Crankshaft Vibration Dampers have a precision machined inner bore which requires special attention prior to installing.

PRO/RACER “ALL STEEL” Dampers far exceed SFI Spec 18.1 and feature specially formulated bonded elastomer, are 100% CNC machined and have an “All Steel” construction.
It is also important to note that your PRO/RACER Damper is supplied “IN BALANCE” condition, therefore, if any balancing operations are to be carried out on the engine, weight must be added or removed from the crankshaft only.
To view our complete application list please contact us

Pro Race Graham Withers is Australia’s Premier Drag Racing Champion from the 1960’s and 1970’s.

During his racing career Graham broke every outright speed and elapsed time record at every drag racing strip across Australia, and was Australian Champion on three Occasion in a race car that he himself built.

After retiring in the mid 70’s Graham turned his attention to business with the same passion, drive and commitments he displayed during his racing career.  Capitalizing on his racing experience and know how, he established a retailing operation for high performance automotive components.

The SEMA Show is the premier automotive specialty products trade event in the world.

It draws the industry’s brightest minds and hottest products to one place, the Las Vegas Convention Center. In addition, the SEMA Show provides attendees with educational seminars, product demonstrations, special events, networking opportunities and more.

Here are some highlights from the 2016 Show.



In August of this year Graham Withers will turn 75 years young and is still heavily involved in business and his love for Drag Racing. I speak to many people who revisit the ‘Good Old Days’ of the antics that they and Graham would get up to whether it was racing to work in their ‘pride and joy’ cars of that era or at the Riverside Raceway back in mid 1960’s. Others reminisce about the days that they grew up with Graham visiting him at his speed shop in Cheltenham or watching him on the various tracks in Australia in the ‘Ampol GT’ or his funny car ‘Demons Disciple’ which not only did he race ‘aswell as other drivers’, Graham also built the chassis for the funny car. Till my next blog J.