Built with GM’s engineering expertise, ACDelco and OEM GM parts are factory original equipment replacement parts for your Chevy, Buick, Cadillac, GMC, Saturn, Pontiac, Oldsmobile or Hummer. Every ACDelco and OEM GM part is rigidly held to federal safety and quality standards and is guaranteed by GM Replacement Parts Limited Warranty. You can trust GM Genuine Parts when ordering this Timing Cover for your 1984 GMC vehicle. GM Parts & Accessories Limited Warranty.