YT 6720-M10 Platinum Race Rockers

To Suit PRC LS Race Cylinder Heads

No other rocker system compares with the Yella Terra Platinum Race Series. Manufactured and assembled in Australia using premium-quality materials and components sourced locally and from the USA, the YT 6720-M10 has been purpose-designed for PRC LS cylinder heads featuring relocated valves and a 13-degree valve angle.

The PRC heads are manufactured with as-cast rocker pedestals designed for factory-style rocker arms. Installation of the YT 6720-M10 requires these pedestals to be professionally machined to the correct height, then accurately drilled and tapped for the supplied M10 mounting hardware.

Engineered for high-RPM, high-boost, high-compression and solid-roller or short travel lifter combinations, the YT 6720-M10 provides the strength, stability and valvetrain control required for serious race and strip application.

Platinum Race Technology

Our wide range of true rocker ratios allows engine builders to achieve increased valve lift without relying solely on aggressive camshaft lobe profiles.

Producing additional lift through the rocker ratio can reduce the severe acceleration and inertia loads placed on lifters and pushrods by the violent camshaft ramp rates often required to achieve high valve lift.

 The YT 6720-M10 uses Yella Terra’s proven bolt-on shaft-mount design with heavy-duty M10 hardware with a 1.7 ratio.

 Why Choose Platinum?

• Wide-body rocker arms provide exceptional strength and resistance to deflection.
• Extruded from aircraft-grade aluminium for high-RPM capability and effective dissipation of excess valvetrain heat.
• Rated to withstand up to 800 lbs maximum open valve-spring pressure, subject to correct installation and valvetrain setup.
• Oversize, full-complement caged bearings are specifically designed for oscillating rocker-arm loads.
• Oversize precision-ground trunnions help reduce friction and improve stability.
• Intricately balanced CNC-machined arms promote consistent valvetrain operation across the complete engine.
• Common-shaft mounting secures the intake and exhaust rockers across a larger mounting footprint, substantially increasing stability and clamp load.
• Offset intake rockers accommodate the PRC cylinder head’s relocated valve and port configuration.
• High rocker ratios provide the opportunity to achieve additional valve lift with both stock and aftermarket camshaft profiles.
• Hardened and precision-ground chrome-moly steel roller tips reduce valve-tip and valve-guide wear.
• Large-diameter roller tips are positively retained by internal circlips for maximum security.
• Full-roller construction provides smoother and quieter operation while helping maintain consistent valve lash.
• Adjustable design allows accurate setting of hydraulic-lifter preload or solid-lifter valve lash.
• Australian-designed, manufactured and assembled.

Important Machining Requirements

 These rockers are not a direct bolt-on installation.

 The PRC cylinder heads have as-cast rocker pedestals that must be:

1. Machined down to the specified mounting height.
2. Accurately positioned and drilled.
3. Tapped to accept the supplied M10 mounting hardware.
4. Checked for correct shaft alignment and thread engagement.
5. Checked for rocker, pushrod, spring, retainer and valve-cover clearance throughout the complete valve-lift cycle.

 All pedestal machining must be performed by a competent engine builder or cylinder-head specialist using the correct dimensions and machining procedures.

 Some clearancing of the cylinder head casting may be required. Any necessary clearance must be removed from the cylinder head—not from the rocker arms.

 Grinding or modifying the rocker arms will compromise their strength and void the product warranty.

 Installation Requirements

• May require YT 5123 25mm valve-cover spacers or taller rocker covers.
• Pushrod length must be measured during final assembly.
• Standard LS pushrod lengths must not be assumed to be correct.

Technical Specifications