Hi;This sounds like a very simple project!Car is a 48 Lincoln with a 50s Cad engine.Just bought it,Has 2 6volt batteries hooked to a relay that IK believe supplies 12 volts to the starter.The Factory gauge shows proper discharge etc with lights etc.Has ythe voltage regulator on firewall and all wires look to be original.Now the thing is has a 6 volt positive ground Alternator.Hooked with single wire feeding direct to the battery!Checked with volt meter it is charging OK.Trying to figure how to get the charge to show on the factory gauge?The alrenator does have the 2 prong plug labeled R@F that probably would have been hooked up in normal installation.Is a DelcoRemy labeled 12volt neg but apparently has breen remodeled to 6 volt positive.Any ideas?THanks.