My 74 260Z was giving me fits electrically, not charging battery, dim lights, poor output at alternator and not wanting to start when warm(12.5V at battery and terminal at starter). I had the starter, battery and alternator all tested, all tested out good. Last night out of curiousity, I pulled the regulator and the cover off the regulator. It had contact points in it that are adjustable. I sanded the contacts, put it back in this morning, now charging 13.8 volts when revved a little and 13.1 at idle. I drove it to work today, shut it off, hit the key and she lit right off like she should. Just thought I'd let you all know that a bad regulator can cause more the poor charging.