I have a 67 coronet with pretty much everything new..
Guy who rebuilt my alternator, told me he upgraded it to a 55? amp. Car has an electronic voltage regulator and the gauge has been converted to an volt meter.
After driving the car for a couple of years the Volt meter acts like a amp gauge, lots of fluctiation, both up and down. Have replaced the regulator 3 times, no change..
Last night when I drove it, with my lights on, the gauge actually decharged with the blinkers making the lights dim each blink at idle. When RPM picked up all worked fine.. Now I am aware of these old stock alternators not charging much at idle, but I am pretty sure everything worked pretty darn good when this car was first back on the road.. Wonder if this is my alternator going bad?? any thoughts on here...

it could be a few things.
first off, square back or round back alt?
single field or duel field vr?

ground to the vr?
voltage to the voltage reg?
voltage at the battery
car off,car running idle, car at 2k rpm.