Reply to "tank fuel pickup/sender"

You can adjust the fuel tank gauge reading by removing the sender and bending the long arm up or down slightly. This is an iterative process but if you've removed the glass from the left side rear quarter window, it's a 5 minute deal to pull & replace the sender with tank in car.
When adjusting, do NOT strain the right-angle bend going into the plastic resistor box- the arm wire is pretty stiff and will crack there if worked much. When I alter senders for in-tank electric pumps or increase their ID for larger capacity engines (stock fuel-out line diameters power-limit an engine to about 400 bhp), they always need adjusting for the car they'll be used in.

BTW, the red 'low-fuel' light in the gauge comes on at about 2-gallons-to-empty when things are adjusted correctly. On a good-running 351-C, that gives around a 30 mile range to find a station you like. Finally, if preferred, your old brass float if in good condition will fit the new sender. But hollow brass floats can leak while the black nitrophyl foam never does (in regular gas; lg. amounts of alcohol is another story).