Timing Chain Kit Fits Buick GMC Chevrolet Cadillac XT4 XT5 XT6 CT4. Utilizes the latest in design and material technology, ensuring quiet and maintenance-free experience. Specialized designs yield significant and noticeable improvements to your car engine. Replace OE Part #: 55514729, 12709437, 55496987, 55505568, 55509047, 55508496, 55496982, 55510030, 55496981.