Automatic Compression Release (ACR) valves reduce the strain of starting your high performance motor by reducing cylinder compression - automatically! The engine is easier to turn over resulting in less wear on your starter and battery. After start, the ACR valves close to restore full compression.
Fits 2007-2017 Twin Cam-equipped models. Can be used with Original Equipment or Screamin' Eagle Cylinder Heads. Does not fit with Twin-Cooled tm. engines.