What's the deal with...

My gas cap seems to seal just fine...never seen the quarter wet from gas and I generally fill her within one gallon full. ...Also, when I pump gas into my '66 Barra. I hold the pump nozzle upside down (butt end in 12 o'clock position)which prevents any spillage during refueling.
X2. Except for the obvious careless filling of the tank, most of the leaks I've seen on those early A-bodies were from damaged caps and/or filler necks. I've run across lots and lots of necks that were damaged from someone trying to install the '67-up gas caps.