I've read on other posts that before hanging the engine you should definitely install the fitting for oil pressure because it's very hard to install it after hanging. Is this the fitting? Mine is a Mattituck IO360.
https://www.aircraftspruce.com/catalog/eppages/oilfuelflow05-11908.php?clickkey=50474
https://www.aircraftspruce.com/catalog/eppages/oilfuelflow05-11908.php?clickkey=50474