Fuel spillage

I am having a problem with my 64 Valiant, when you fill it up it does not spill out of the filler neck, but it does so after you have driven the car, you park it go in the store come out to find it is puking gas out the filler neck, it has ruined the paint it does it so much, I was thinking that there was something wrong with the vent tube, but can't find any problem with it. I have looked at where the cap threads to the filler neck and it looks ok, I have put a NOS gas cap on it seals good, I still get fuel spilling out. Has anyone experienced this if so what did you do to solve it. I am getting frustrated with this problem, as this is my girls daily driver. Thanks in Advance........

The system is a little older than I'm used to dealing with. Does it have a return line? Vents?

This is a problem with some of the early A's. There is a vent line that runs up the side of the fuel filler neck then out around the left inner fenderwell that will plug up sometimes. Make sure it is venting properly.

Laysons has a fix for it. They weld a piece of metal in the neck & supply a removeable plug that fits in it. Kinda' expensive. Do a search for posts by Rick at Laysons (not sure of his exact screen name). He posted some pics of it a while back. You might be able to do something similar on your own.