Let's assume the problem is not with the carb.
There are 3 pieces of "rubber" fuel line in the system.
If they are old, they need to be replaced to
ensure you aren't drawing air into the system through an
age crack in the old hose, or perhaps a blockage in the hose.
One is at the fuel tank, connects the sender to the pipe.
One is in the area of the front passenger foot well, connects
the pipe to the next pipe.
The other is from that pipe to the fuel pump inlet.
It is a pretty easy job to replace these pieces with new line.
I think the diameter is 5/16".
It could be the problem is with the fuel sock on the sending unit. If
the tank has rust in it, the sock will plug. While it isn't a terrible job to
get the sending unit out, it takes a while.
If you suspect the sock, but would rather not get into the sending unit,
you could try running the car from an aux fuel tank. Run a long
piece of fuel hose from the fuel pump inlet to an aux tank which
you could place in the pass front seat. Have someone hold the aux tank
so you don't get spills. If the carb performs off the aux tank system, you
know where your fuel restriction is (or isn't).