Ultralite
Yella Terra’s exclusive Ultralite rocker arm, shaft and pedestal system offers 50% less nose weight than the factory rocker system, the result being greater RPM potential without compromising strength or durability. The perfect low-maintenance substitute for factory rocker arms which utilise problematic cage-less bearings, solid non-roller tips and heavy steel bodies.
Yella Terra Ultralite is ideal for high revving street applications when coupled with factory/lightweight aftermarket springs. Manufactured and assembled in Australia using the highest quality materials and componentry consistent with those found in our Platinum race series.
Our wide range of true ratios allows you to achieve high lift without relying solely on your camshaft… a trend many engine builders and racers alike are adopting to relieve the inertia on lifters and pushrods generated by aggressive and often violent ramp rates required to make big lift.
Don't fall victim to bearing/trunnion upgrades which only address half the shortcomings of OEM rockers.
Why Choose Ultralite?
- Built to withstand 400lbs* max open spring pressure
- Oversize full-complement caged bearings designed for oscillating (rocking) loads, paired with oversize precision ground trunnions to reduce friction.
- Intricately balanced lightweight arms ensuring vital valvetrain stability - focusing attention on the harmony of the entire engine. 50% less oscillating nose weight eliminates valve float in upper RPM range allowing for higher rev ceiling.
- Extruded from aircraft grade aluminium, perfect for dissipating excess top-end heat.
- Proven bolt-on shaft mount design that mounts both inlet/exhaust to common shaft, effectively increasing footprint and clamp load twofold without any further cylinder head modification.
- Various ratios available, catering for every camshaft grind. High ratios allow for additional lift on stock and aftermarket camshafts.
- Chrome moly steel hardened and ground roller tips of generous diameter (positively retained by internal circlip) preventing abrasion of valve tips and guides commonly seen with non-roller tip rockers. Allows for smoother, quieter operation. Maintains lash and reduces necessary and tedious engine maintenance.
WARNING:
- These rockers are recommended to a maximum spring seat pressure of 380 lbs.
- Use as a replacement for factory heads with factory lightweight springs.
- Shafts centres must be M8 threads.
- Not recommended with flat tappets/solid lifters
Please note: Requires YT 5132 10mm valve cover spacer.
Also note: Due to inconsistencies in GM castings, these rockers may require clearancing on the heads in the locations pictured.
Tech Spec:
PART NO | YT 6646 |
BRAND | ULTRALITE |
APPLICATION | FACTORY REPLACEMENT/STREET |
MAX OPEN SPRING PRESSURE |
400lbs |
MAKE | CHEVROLET |
ENGINE | LS1/LS2 |
MOUNTING STYLE | SHAFT MOUNT |
ROCKER ARM RATIO | 1.8 |
STUD SIZE | 8mm |
ADJUSTABLE/HYDRAULIC | HYDRAULIC |
ROCKER ARM STYLE | FULL ROLLER |
ROCKER MATERIAL | ALUMINIUM |
ROCKER ARM BODY STYLE | STANDARD |
ROCKER ARM NUT STYLE | CAPSCREW |
MAX SPRING DIAMETER | 1.437" |
INLET OFFSET | NO |
QTY | SET OF 16 |
NOTE |