I am involved with a 1980 Trans Am and it needs a gas tank. I have a perfect one that I saved because I had coated it in POR-15 and then undercoat before it was even used for a couple of years. I know that the difference between the '74-'78 and '79-'81 is that the filler tube is short on one and longer on the other. But which is which? I can't remember. Worse, I think this '80 has the shorter fill tube tank for some reason. The gas cap seems too far down in the hole. Or is that the right one? Anyone know?