There are many compelling reasons why a shaft rocker system is preferred over stud-mount rocker arms —even in high performance street applications.
In a standard stud-mount setup the fulcrum point is fixed, and often it isn’t perfectly aligned between the tip of the valve and the pushrod —causing side loading that robs power and is detrimental to valve train component life. The geometry can be optimized in a shaft system.
The most important factor favoring the shaft system is valve train stability. Because rocker arm studs tend to flex and alter the geometry it is imperative that a “band-aide” device like a stud girdle be employed for any kind of serious performance build. But extensive Spintron testing has confirmed that it’s not as stable as a shaft system.
One important benefit of this stability is that it’s possible to maintain the desired valve lash better. Settings are rock-solid.
Cost used to be a major factor, but with the advent of T&D’s SportComp series shaft systems for the most popular applications that’s no longer the case. They come in a variety of ratios to improve performance. When you add up the cost for upgraded rocker arm studs, aftermarket roller rockers, stud girdles and pushrod guide plates it’s a no-brainer. And, in many stud girdle applications, raised valve covers are required.
For competition applications where every possible ounce of performance is desired, T&D shaft systems provide the advantages of optimum fulcrum position, provisions for offsets, absolute minimum mass moment of inertia, etc.
If you’re serious about maximizing horsepower and engine life, there’s a T&D shaft rocker arm system ideally suited to your application and budget.