filler neck modification

Fairly new to this forum and just recently took deliver of a 70 Duster, so I apologize if this issue has already been addressed. My unfortunate story relating to the fuel filler is when I tried to fill up the car here in California as soon as I hit the lever I was met with a stream of gas coming back at me past the emissions bellows that are mandatory here. Tried to reposition the nozzle, but was met with the same results. This led me to only putting 2 gallons of fuel in it, which took me a little over 5 minutes. Has anyone had this problem and if so developed a fix for it? I am at the point of getting 5 gallon gas cans and filling the car in this fashion.