Mancini rear seal.

Also found when measuring aftermarket seal hsgs for seal depth that the two I measured were about 0.018" shorter than a factory housing, which itself was a little shorter than the corresponding depth of the seal groove in the block. This would not be a problem with a rope seal which conforms to shape, but a Neoprene/Silicon seal will be compressed more on the hsg side. So the seal is 'squashed' more & pressure on the crank will be uneven & the seal will probably wear more quickly where the pressure is greatest. I used the factory hsg because of it's more uniform dimensions.