New to me Barracuda with Mopar Crate 390hp low oil pressure

Looks like the to the rear of the intake manifold.
With the sensor in that position it may read a bit toward the low side. As it is at the end of the oil galley.
If your filter adapter has a plug in it try applying a mechanical gauge there it may be more of a true reading.
Filters can make a difference, try a different filter, I use WIX non racing filters - no issues
Good luck