[1project2many]

I'm going to add a vapor purge line to the top of the vent hose at the filler neck. The valve is going to help keep the tank from being overfilled. When the fuel level gets high enough the ball "closes" the filler tube and the fill valve on the pump is supposed to click off. The ball will also help keep large amounts of fuel from sloshing up the fill pipe if the tank is near full and you go around a corner. Liquid fuel is not supposed to go through the vapor lines or bad things happen. Yes it's a little more complicated but it's going to require the least amount of modification to the existing system in the long run.

One thing I've figured out over the years is to know approximately how much gas your truck is going to take and don't be tempted to add more after the pump cuts off.

Right now the pump cuts off when fuel is at the end of the nozzle, about 5" from the top of the neck. I usually only fill it until I can hear fuel gurgling in the neck which is a bit lower.

That's of my project, and that ball is in the neck, not the tank.

Thanks. That helps. It was really hard to tell from the picture. Now I know I don't have to cut up a tank to get one.

I have one I took off that has a flapper inside the top to keep it from sloshing out.

Thanks. So far, it looks like the flapper type is mainly for fuel slosh but the ball type does the automatic shutoff as well.