Hello, those references "8 norte" and "4 oeste" are a reference system specific to the city of Mendoza, where I'm from. It's based on a system of axes, as if they were Cartesian, the vertical axis is the San Martin avenue And the horizontal axis is 3 different streets: José Vicente Zapata, Colón and Arístides Villanueva. Returning to your question, 8 North refers to the street or streets that are 8 blocks north of the horizontal axis, and the same with 4 West, which is 4 blocks west of the vertical axis.
I invite you to look at the street signs on Google Streetview and see for yourself what I mean.
Greetings and I hope you understood this.