Okay here's some background...

1989 5.0 F-150 front tank is rusted and leaks gas constantly at a dripping rate.
Rear tank has never worked and nether works with my fuel gauge (but that's another problem for another time), I figured it was the selector valve or low pressure fuel pump in the tank. I guessed the former owner never switched the tank so my guess is the selector is shot.

So I had this idea to just switch the fuel lines and take the front tank lines and put them on the rear ports on the selector valve and vice versa for a temp fix, until it warms up and I'm less broke.

Well, seemed to have worked... So I thought... Drove around and everything seemed fine, I knew my front tank was on fumes and I drove pretty much all day with no sputtering or grabbing air (no fuel gauge so I know when my truck is low on gas... lol) so I figured I had fixed it and all is well, well, not really... I parked at a gas station last night to get a drink and turned my truck off, got back in and tried to turn it over and it wouldn't, it was cranking like a champ but there was just no fuel... I could even tell there wasn't any because I could hear the high pressure fuel pumps sound change (sounds lower pitched if there isn't fuel in it)... I pushed it to a gas pump put gas in the FRONT tank and it starts right up... So wtf?

Obviously it didn't feed gas from the REAR to the FRONT but I know I had to have been running from the REAR tank as I used my truck a lot yesterday... I don't know but I don't think I could be any more confused at this point.

Anyway, I've gotta fix this so I got some weird question(s)
Okay with both of the REAR tank lines disconnected they both leak fuel from them, one more than the other, one has a constant drip and the other one gushes fuel (my REAR tank is pretty full) wouldn't the one that leaks fuel the most be the supply and the one that leaks the least be the return? I just want to be sure I understood the diagram right (which I've linked)



EDIT:
And I just remembered, the supply ports/lines and larger than the return ports/lines... So you can't really screw them up... Thus kind of making this whole thread slightly pointless YET I still have this problem... oh wth.

 

Update and bump...

Well, I ran out of gas, from what I figure was residual gas in the front tank... So it's still pulling from the front tank, how? How is that possible? What am I missing? There must be something...