COMP Cams Spring Seats Cnc .100X.535X1.The old standard shims will not hold up to the extreme spring pressures and high RPM in today's race engines. COMP Cams offers a simple but effective solution to this problem. These Valve Spring Locators provide a thin, hardened Steel alloy seat that will not only protect the head and shim, but also locate and hold the spring in place. Previously, this part has been available only in a cup form with the retaining portion being on the outside of the