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I have a 1965 fastback that is in show quality condition. The one thing I can't seem to figure out is why the lights dim when I rev the engine. The headlights, dash and other interior lights dim. I put in a new battery with 800 cold cranking amps. The altenator appears shows as good. Is my problem a voltage regulator or something else? Please help, it's driving me crazy.
 

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Sounds like a voltage regulator issue, especially if it's one of the point-type electro-mechanical ones. They do some funky things with lighting, but the good news is that it's usually only an annoyance, and it is charging. The usual fix is going to a solid-state replacement (I recommend the Motorcraft replacement), but you may not want to, in order to preserve the show car integrity.
 

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I would recommend checking the ground on the back of the pass head, check the alt belt tension, if those are okay, then use a voltmeter to check the voltage on the battery at idle, and when the engine has some higher rpms say around 2000, it will take a minute for all reading to stabilize due to the capacity of the battery, then take another reading at 2000 with everything electrical on and max, like heater blowing on high speed, headlights on, no turn signals since they flash on and off, and post your results. This will help to determine if the charging system is not working correctly. Worn brushes in the alt can cause your problem, as well as a regulator. I wouldn't recommend buying any parts yets. Good Luck.
 
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