My 68 Hemi Coronet is very nice, but leaks about a 1/2 cup of fuel onto garage floor after a drive. It's tank was replaced by previous owner and I think is the correct tank. The 2 vent lines are aftermarket, one is connected to the inboard vent nipple at the front of the tank, while the other J-shaped short tube is connected to the outer nipple at front of tank. If the tank is only half full or more, it leaves a puddle of fuel on the ground which is embarrassing at car shows. It has the correct non-vented cap. I don't know how the 2 vent lines work, but I snaked a thin wire into the nipple with a small hook on the end to see how far into tank they go. The inboard one feels like it is only about 8 inches long, while the outboard one is long and extends way rearward to the back of the tank. I tried swapping the 2 vent tubes so the snaked trunk one was on the long outboard vent nipple, and the J-shaped vent line was on the inboard short nipple, and it leaked even worse. In 40 plus years with many Mopars, I have never had this problem. I considered buying another aftermarket tank, but am afraid it will do the same thing. Any ideas please?