Review on 🔍 Rear Engine Main Seal Set - Fel-Pro BS 11829-1: Optimize Your Search by Darryl Blumenthal

Lots of information on the web about old cranks that have a worn groove on the rear main sealing surface. Replacing a leaking rear main oil seal with the exact same seal or a different brand seal made to OEM specifications will ensure the leak returns quickly. This gasket is designed so that the sealing lip is offset from the position normally specified by the OEM (in this case a GM/1981 Chevy 350 block). When the sealing lip is moved a few mm, the lip slides over the fresh sealing surface. Unlike a worn, jagged crank head that will quickly gnaw at the sealing lip, a fresh crank sealing surface should interact with the lip seal like a new one. Anyway, this is a theory. All I know is that it worked for me - no more oil stains under the rear main.