Probably time for new lines. My 66 Dart tank looked like a cave inside with stalactites of rust even after cleaning. Time for a new tank and lines. I did that about 15 years ago with no issues since.
The car I brought came from Arizona.
Only very very light rust on exposed steel.
So clean I gave the entire exhaust intact to the guy who bought my '68 notch.
But on the drag strip in particular was having a problem losing fuel pressure at the end of the track. Fought the problem for a long time. Changed the sock. Tried different pumps. etc.
In the end I'm convinced it was just enough of a pin hole or rust in the section going over the axle - near the exhaust.
