1972 Duster Project - Back From The Pasture

Didn't I read the following correctly...?
"We pulled the distributor and tried to prime the oil pump with a drill, got a little pressure but it never made it up to the valve train. Rolled it over a little by hand to get the journals opened up and tried to prime again....nothing to the top.

It rolled over very smooth from the start, nothing stuck at all, which surprised us but good news none the less. I am however curious why I didn't get pressure to the top end.

My thoughts are 1. The Marvel is too thin to pressurize up top. 2. The pickup tube is gunked up and can't pick up."

This pertains to what I wrote about the "timed" oil passages that direct the oil to the top end.