Rear main seal

[D.PASSMORE]

Originally Posted by 67 chevelle

This is a common problem , most older small block chevys leak , the rear main is notorious , the seal can be installed backwards and cause a leak , where the 2 halfs of the seal meet should be offset 3/8 of an inch from the edge of the block [per felpro] , a good working pcv valve will help prevent and in some cases [few] cure leaks , other areas in the back of the engine that commonly leak are , oil sender , where the intake and block come together , distributor seal , valve covers .

Generally when the rear main is the culprit it slings oil onto the flexplate or flywheel
I along with most others on this board im sure "FEEL YOUR PAIN'

X2, if you rebuilt your own motors before crate engines. The rear main seal in a SBC was always a PIA. You would cross your fingers when breaking in the motor. The lift that my G-Pa had in his barn was a blessing. The 3/8 offset method was what we always went with. Even then it wasn't a 100% success.