Think Packard used the AJ style pump and if so, this from a Motor's Manual might help as it has a bit on valves. Ignore the extra R type photos on page two.
Attach file:
AJ1.jpeg (173.25 KB)
AJ2.jpeg (375.78 KB)
AJ3.jpeg (365.33 KB)
AJ4.jpeg (336.57 KB)
AJ5.jpeg (137.58 KB)
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