What was the outcome of this? I have a 63 that was doing the same thing. Right around 1/4 a tank it would die. Let it sit and it would start and die 5 min later. I am having the tank boiled right now and will coat it. I cannot for the life of me find where to purchase the gas line that goes from top of tank to the pump. In the parts catalogs they have them for most other years but not 63