Another thing Milodon pointed out was that rear section is not filled 100% with oil. By necessity, it's mostly filled with the oil pump. Remember that's what the section is for. Especially if you are using a high volume taller pump, the body will displace most of that rear section.

If you where running a small block with an external pump, you could eliminate that section and run the cutout all the way to the back of the pan.