Good luck to the OP, but this makes me curious about my own block that's half assembled. Does the Magnum 360 have that oil plug? I don't remember seeing one and want to make sure I'm not missing something.
The Magnum blocks have the same size cup plug in the same spot. To know if it's there or not, stick a piece of stiff wire or a long , skinny screwdriver down the oil psi sender hole. The plug is about 7" down, maybe a little more.