Suggestion for finding correct instrument voltage limiter for 67 Dart

I was testing the voltage by disconnecting the gas tank sending unit wire. Old instrument panel voltage regulator turns on and off to control the voltage. Didn't know that. I ordered the one from Year One like other replacements that are constant voltage. It fit with some minor adjustments to the tabs so it would fit the slot pattern on the PC board. As the instructions said with the constant voltage one the gauge goes up slowly when the ignition is turned on verses the original ones quicker reaction.