I agree with everything Nyles posted. In addition I want to add my experience:
We're dealing in very old cars, here. We northerners suffer 'rust belt' problems that they don't have out west or down south.
Your pickup inside the tank has a fine mesh on the bottom of what looks like an inverted cup. Today's gas is not anything like it was back in the day. Today's gasohol sucks up water. 1980 gas (and earlier) would not mix with water, and it caused a lot of tank rust, line rust, etc. In winter, we used to buy 'drygas' which was exactly what's in modern gas.
Rust has nowhere to go in your tank. Fine particles clog the pickup until it backwashes some away. I pulled five handfuls of rust out of my '55 Ford gas tank.
The fuel line goes up and back down which is ok if the siphon isn't broken by:
A pinhole in the steel fuel tube (including inside the fuel tank),
A pinhole in a rubber hose,
A leaking connection,
The check valve inside the fuel pump is broken.
Two hundred buys a tank from rockauto.com (with our discount), steel fuel line costs under ten bucks and a foot of rubber hose costs another dollar. So, for ~$211.00 you can have a new fuel system. That's what I would do. - Dave