"Why would I need a voltage reducer?"
So you do not "fry" the fuel gauge.
Some people say they/you do not need it.
Most people who do not use it end up losing the gauge.
It is much cheaper than buying a used/new gauge.
Here is the correct type of reducer - it is a nice version because it cannot be installed backwards (it works in only one direction/orientation).
https://www.classicparts.com/1947-54-Gas-Gauge-Voltage-Reducer/productinfo/24-995/It goes on the "input" side of the gauge ("behind" the Empty marking on the gauge). It does not go on the side of the gauge where the sender wire is attached.
