Welcome, my friend, to the world of Ford!
I first had this problem in 1967 with my 250, then in 1991 with my new 250 diesel and now with my Ranger!. What the problem is is the filler tube goes between the frame and bed and is somewhat pinched, which causes the air in the tank to fight the fuel going in as the air tries to exit.
The way I deal with it is to hold the nozzle correctly (That way you avid spillage)but up as high as I can tilt it. For some reason this allows the air out while fuel is going in.
The other issue is because of the air not being able to exit quickly, as the tank fills, the fuel will shut off the pump when it hits the sensor in the nozzle. I have found that I usually put 2-3 gallons in when the automatic cutoff stops the filling. With the nozzle still as high as I can get it and maintain a seal, I slowly pump till the tank is full.
When I first got my 67, I was invited to a meeting with other owners to tell Ford what they could improve. There were about 20 of us there and every one complained about filling the tanks. You can see how well they listened!
Good luck filling the tank!
Lee
2001 36' Kountry Star DP