Fuel supply problem

Hi All,

My 77 ran into a fuel supply problem last week. Low fuel
supply to the carb. Anything over a third throttle and the
car would start to stumble, full throttle and it falls on
its face. First change the filter, still not enough fuel.
Went out and bought a new fuel pump, and still not enough
fuel. Then I noticed that no fuel was coming out of the
fuel line from the tank, especially after filling it. So I ran
some compressed air from the fuelline by the pump into
the gastank with the gascap removed. I blew away whatever
was obstructing the fuel line. Now it flows freely. The question
I have is is there some kind of screen covering the fuel inlet
or is it sucking something from the bottom? Im thinking of trying
to siphon whatever it is out before removing the tank. If its
sediment like material, this should work.
The car runs great now but am worried about getting plugged again.
Im sure whatever plugged the line is still floating around
in the tank. This car sits in the garage a lot sometimes for
months at a time when I am away. Please reply to this group, my
email addy is nogood.

TIA
Tom

77 L-48
73 LS-4