On my 67 400 convertible I have been having a problem. I have a new battery and after a few times out yesterday, the car would not start. I took off the alternator and had it load tested - 15 volts. I changed the electrical plug in the back as it looked and seemed a little loose and charged the battery back up. Today the exact same scenario, out of a few times and dead. Had the battery tested and it was fine. I put my volt meter back on and it read 12 volts and when I cranked it it dropped to 3-4 volts. I jumped the car and the battery recovered to 12 BUT never went above 12 so it is not getting the charge for the alternator. So, I changed the voltage regulator and jumped the car AGAIN and the battery was charging at 13 volts at idle and 13.2 at throttle. The 13-13.2 seemed to be a little low for the charge rate. Does anyone know what your charge rate is or what it should be. It fired right up after a long drive without an external charge. Hopefully this resolved the issue!