Designed for high-performance street and racing applications, our new RPM Xtreme cylinder heads give you the best combination of as-cast port design and CNC porting technology. This proven combination provides you with a powerful cylinder head at a lower cost than a typical fully CNC'd head. They feature an 18� valve angle, CNC-machined 59cc combustion chambers, 185cc intake ports, lightweight 2.02" intake valves with 8mm stems, and beehive valve springs.