RDE 62188 Timing Chain Damper for LS1 and LS6 Blocks *LS1/LS6 ONLY - Will not fit later engine blocks* Designed to mimic GM 88958607, these dampeners will fit GM Gen III** LS blocks that came from the factory with the holes already drilled and tapped. Engine fitment includes LS1, LS6 and some early truck engines. Will NOT fit Gen 4 blocks. Dampeners will work with either single row or double row chains. The bolt spacing measures ~2.1” center to center and the dampener is machined from a high temperature, low friction nylon. ** Due to variations in GM manufacturing, some 2004 later model blocks as well as reproduction blocks may have the narrower LS2 bolt spacing of 1.7”. Please verify hole existence and spacing on your block before purchase. Made in the USA!!