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Having a similar charging issue on my girl’s 68 Polara. Around 10v at idle, revs up to 15.5 at about 3000. Alternator is a new AcDelco 3342086, regulator is a new replacement but I don’t have much faith in it.
That Mopar regulator looks like a better bet, will it play nice with the Delco alternator? Where can I get the harness for it?
 

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. . . Having a similar charging issue on my girl’s 68 Polara. Around 10v at idle, revs up to 15.5 at about 3000. Alternator is a new AcDelco 3342086, . . . .
Which replacement alternator do you have? See attached image. Is it the one wire field terminal (1968) or 2 wire field terminal (1970 & later)?

Auto part Clutch part Automotive alternator Computer cooling Automotive engine part

. . . regulator is a new replacement but I don’t have much faith in it. . . .
Do you have an image of the replacement voltage regulator or a part number that one can search and find an image and description?
 

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Regulator is a Delco C647. I jumpered the positive battery terminal to the black wire’s lug on the regulator and the charging came up to a better level, so I’m wondering where the 12v current to that lug is getting compromised, maybe at the bulkhead connector?

68RT, thanks for posting that link. I’ll be reading it today.
 

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. . . Regulator is a Delco C647. . . .
So you have a replacement electromechanical voltage regulator that Chrysler used before 1970. It provides constant 12 volt power input to the regulator.

. . . I jumpered the positive battery terminal to the black wire’s lug on the regulator and the charging came up to a better level, so I’m wondering where the 12v current to that lug is getting compromised, maybe at the bulkhead connector? . . . .
This indicates that appropriate, constant power is NOT being sent to the voltage regulator. In the link 68RT made in post #23, scroll to the end and a schematic wiring diagram is presented for the electromechanical voltage regulator. Use that to start your wire tracing.
 
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