Meets or exceeds all original equipment specifications Unsurpassed quality for you can trust Validated for fit, form, and function Designed for repair and everyday environment Timing Chain Cover Set Timing Tab For 55-95 Chevy SB 283-400 The timing chain cover is responsible for keeping dirt and debris from entering the inside of the engine. Due to the fact that the timing chain and belt are housed inside the engine, the timing chain cover even helps to keep the timing belt or timin chain solid and secure for smooth operation