The plug hole is not a fill-to-spill like a transmission or Diff.
Moroso instructions calls out 8 qts, and that does not include filling the
oil filter.
Then running the engine. Shutting down and adjust the dipstick to the Full mark.
All the above assumes your not running a remote filter and or
oil cooler.
I'd baseline the system with a
filled block mounted
oil filter and 8 qts in the pan. Set the dipstick. then re-add the cooler and remote housing. Service engine oil level to the full mark you set earlier.