I like to think I'm familiar with every Milodon Mopar oil pump of the last 50 years but I've never seen one like that.
Guess you haven't looked in a Milodon catalog in the past ten years ... these aren't new !!
FWIW, now that I see the pump open I recall drain back issues being related to the design of Milodon's rotor design. If you were using a standard HV pump with a Milodon block plate for external pickup you would have no issues with drain back.
