Alternative "rope" style rear main crankshaft seal for late 1961 and later big-block engines that were supplied from the factory with molded rubber seals. We offer this package because many re-builders prefer a traditional rope seal to the OE-style rubber seal seal provided in the overhaul gasket sets for these engines. Package includes instructions and side seals as well as trimming knife, shield and spacer (Not for replacement of 1958 to early 1961 rope-style seals)