Brake lines at MC

[C3pilot]

Kind of embarrassed but I’m drawing a blank on which chamber of the master cylinder feeds which brakes. I have a ‘72 LWB 1/2 ton with power disc/drums. Got the truck a few days ago as a bit of a basket case and the brake lines have been pulled and bent/damaged.

I searched and have seen with different brake line routing at the MC, front chamber to the front of portioning valve and rear to the rear of PV. But…I’ve also seen it the opposite with the front plumed to the rear port of the PV.

Any input would be awesome!