Re: GM 1 wire alternator not charging battery
I agree with Vintage '68 and bone up on the one wire alternators.
When I had my '71, I went to the one wire alternator and did not like it. The one wire setup would only charge the battery, under load. It was particularly noticeable at night when the lights were on. It was very annoying to have the lights dim, when your're stopped sitting at a light. As soon as the RPM's picked up, the lights would get brighter.
If you can, go back to the three wire setup.
Just my 02 cents.