red
Being a lake bum in Texas
My tank doesn't have the 1/2" hose barb for that.I just grabbed random pic to show that all filler necks have the secondary tube with it. This is where your other line should connect, back at the point of connection for the main line.
Without it any tank fills too fast it can come out. Plus just driving around the fuel slosh will do it too.
View attachment 53636
Either way though I'm not going to drill a hope in the tank to add that. Anymore fuel tank mods will be done with a combo of 5.56 and 7.62 haha