It was probably left out on a previous reassembly. There will be more oil against the back of the seal, but none of the small block V-8's ran a slinger, and the vast majority of them don't leak. The V-8 seal is almost identical to the one for the 6.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!