I don't have any hands-on experience with Chevy engines of that vintage, but it looks like you've gotten some pretty accurate information already. Slinger-equipped engines without seals were pretty common as industrial engines in the 40's and 50's. I remember rebuilding a Hercules 4-cylinder that powered a water well drill rig, and it did not have seals on either end of the crank, just slingers.

Be sure the drain holes below the slinger are clear, with no sludge buildup. Once the oil slings off the crank, it needs to drain away quickly.
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!