"Pulsing" voltage, RPM drop with load.

The car is originally from AZ so everything is brittle. I've disconnected it once and broke a tab off. My plan is to clean connectors somehow and pack with grease but only want to do once and I am planning an engine swap this winter. Maybe I'm being paranoid.
I agree if it ain't broke don' fix it.... BUT I believe the bulkhead connector plastic parts are reproduced so just a matter of switching over the metal connectors with wires still attached.