[dmsfrr]

Long story, to aid in understanding...
The original '56 and earlier King-Seeley brand gauges used heat sensitive bi-metal switching contacts in their sensors to regulate the flow of current thru the Fuel & Temp gauges. Not a variable resistor.

"New replacement" fuel tank sensors use a variable resistor as a substitute for the old style switching contacts. The sensors usually come from an off-shore manufacturer and may or may not give correct / consistent gauge readings.

Ohm readings? Dennis Carpenter customer service folks would be the first ones to ask. But because they have nothing to do with the long distance manufacturing process they may not know, unless the resistance specs are mentioned in the supplied paperwork.

More background info...
Original '56 gauge electrical parts are 'one-year-only'.
'55 gauges were designed to operate on 6 volts. (Although original pairs can work on 12v.)
'56 was the first year of 12v and the gauges operated on full voltage.
In '57 Ford updated the tank sensor to a variable resistor and a small dash mounted voltage regulator to provide a lower voltage for the gauges.
.