The COMP Cams Cam Phaser Limiter Kit for GM LT4 Engines restricts cam phaser motion so higher performance camshafts can be installed in GM LT4 engines. The kit includes a tool that allows simultaneous compression of phaser springs in 2015 or newer GM LT4 engines, as well as ensures the spring lock engages at its optimal location. Installation of the included limiter plug provides the necessary valve clearance for high-performance camshafts while retaining the benefits of VVT technology. Combining this modification with more aggressive camshaft profiles has resulted in large upper-RPM gains without sacrificing bottom- or mid-range performance.