For 11-on Ford F-150 5.0L Coyote 4 valve engines. For 11-on Ford Mustang 5.0L Coyote 4 valve engines. Fits Ford 5.0L Coyote 4 valve. Valve spring compressor tool kit. Idler Pulley Kit. Simply place your valve spring and retainer in place, place the retainer cap on top of the retainer, and turn the long bolt to compress the springs until the valve keepers can be placed.