Possible solution for early shutoff (gas)

[Cdash]

I found this on a site for Jeep Cherokees (my other toy) and wondered if the same thing would help our superduties? Read below

"Getting more in your tank

I have modified the stock fuel tank to increase the capacity by raising the vent tube inside the tank. You can get at by removing the fuel pump with the tank still in place. Just make sure that you don't have more than a 1/3 of a tank. I added a 90* bend made in aluminium (was a old ski stock that I bent up) and cut a 3/4" long slot in it so I could push it over the end of the vent pipe (5/8"dia.) with some sealer and a stainless steel hose clamp. This raised the vent to about 1/2" short of the top of the tank (80mm higher than stock). When I filled the tank it first stopped at the old level but since then it has filled right to the top. I got a total of 97 litres (25.5 us. gallons) in the tank which is 21 litres or 5.5 gallons extra. I have removed the unleaded flap to improve the speed of the fill and so you can see what is happening. I was always able to get this extra in if I dribbled it in, but it took an extra 15 minutes. So now it is alot quicker and you can carry one Jerry can less on the long trips. If you are worried about the fuel expansion, it would only make a difference if you filled on a cold night or morning and then without driving far you left it in the hot sun. It will then slowly dribble out past the cap until you drove it again or it cooled. It has happened a couple of times to me now that summer is coming on and I had only driven a mile from the service station. If you know you are about to that, then just stop early. Otherwise it maybe better to only raise it 40mm and get half the increase. You only have to drive a 100kms or 60 miles to use the extra fuel to bring it back to stock. I have always put the extra in on long trips and have been in above 40*C (100*F) temperatures for the last 5 years with no problems ever. Someone on the Cherokee list from South Africa has the same mod without any problems as well ( he was able to bend the stock pipe up ). I have since found that by raising it 53 mm that it has stopped the fuel leaking out when left full even when the temperatures were over 40*C ( over 100*F ) so long as the cap was done up tight and the seal is in good condition. This gave a capacity of 90 litres or 23 3/4 gallons."

I have not checked this out on either vehicle yet. Just sounded like the same systems and maybe the same answer.