Is the mopar fuel sender part # 4051004 the correct non-linear sender?
"What I think I know" (and could be wrong) There are no repop senders that have the proper resistance taper. Only someone properly rebuilding your old ones---I thought someone posted a source a short time back---or NOS and good luck finding one
There is an intermediate electronics package you can buy, but I have no idea how well it works with the repop gauges
"Meter match"
TechnoVersions - MeterMatch for Analog Gauge Correction
Help Me Calibrate My Fuel Gauge
Gas gauge calibration unit