Hybrid Performance Mfg LS1 specific timing chain dampener! CNC machined in the USA from a unique polymer alloy that offers exceptional sliding wear resistance, high abrasion resistance and is cryogenic to +350°F. The material has outstanding chemical/oil resistance and does not absorb moisture. Features: Prevents excessive timing chain slap/oscillation under normal and excessive RPM's. Extra wide to accommodate single or double row chains Bolt spacing must measure 2.1” apart. These LS1 specific dampeners are designed to work with blocks that have the mounting holes on a slight angle and offset to the right (see pictures) No oil pump spacers required! What's Included: LS1 Timing Chain Dampener Class 10.9 yellow zinc plated mounting hardware **Due to wide variations across GM's LS based blocks, you must measure for your specific application to determine if this product will work for you *** Blocks without bolt hole provisions can also be drilled and tapped to fit