After I fill up my 1966 T-Bird, I get fuel spillage from the overfill tube when I go into right hand turns. This continues until I've used about 1/4 of the tank (the gauge indicates 5/8 full). The fuel seems to be sloshing up the filler tube and out the over flow tube. Is this a common problem for the 66 Birds? I just let the gas pump shut off normally and do not continue to top it off.

Try a new gas cap.

I tried a new gas cap and unfortunately I'm still getting gas sloshing out of the filler tube

I have 61 bird & my 1/4 vent line (rubber) was a little short. I lenghtened it & no more spill. Check if you have vent near gas cap. DAN

Dollars to Donuts says the "O" ring on your filler tube is shot. Contact John Draxler and order one. I think it's about $5.00. Not a difficult repair to do. Good Luck
Randy Mattson