Not sure why that guy in the article had vacuum problems with his tank. I thought all modern fuel caps let air in, but not out.Found a good writeup on how to do a better tank vent mod
1994-1997 Power Stroke FAQ - Fuel Tank Vent Mod
www.thedieselstop.com
I ran into the same problem he did, not at the beginning, but later on when one of my hoses fell down. I filled the tank and some fuel got in the belly of the vent hose where it fell and sagged. I finally figured it out and lifted the hose and got the fuel out of it, then everything was back to normal. You definitely need a constant downward slope on the vent hose so it will stay drained of fuel.