How do you guys keep gas from spilling? 66' Dart

Ah, interesting.

thats interesting I've never seen that before.
the fix for the fill is the restrictor plate to add more back pressure when filling up.

get the smaller size

gas tank sentry small .jpg

but the total fix was restrictor and a new super nice sealing gas cap so when I make those hard turns a tank that ss really full doen't slosh up and leak out the cap. 3 years of the one friends car and 6 for another. but he did have ot replace his gas cap since it started leaking down the quarters on hard turns. I think he bought one of damnraiders cnc gas caps the have a neoprene o ring To help seal the tank.
link is here
Stop spilling gas