Hi David, (I know, I'm a post grave digger....) I just installed the LM7805 in my 65 and stumbled across your post mentioning the addition of a diode to the ground leg. I have two questions for you, 1. How do i select the diode correctly ( I have a bunch laying around, but am not savvy to sizing one correctly, ie how much current it needs to handle out this ground leg...). 2. As I'm currently just grounding the chip to the CVR case by bolting it down, (middle leg is unconnected inside my CVR case) do I need to isolate the case ground to add a diode to the middle leg, or are they not actually the same ground path somehow? ? (Forgive me if that was a confusing way to word it...)Actual average voltage is 5.5v to 5.7v with an analog meter. If yours is bad and you build your own replacement with a 50-cent 7805 voltage regulator, add a diode to the ground leg to push it up to 5.7 regulated volts. Your gauges will be most accurate at that voltage, though they can be adjusted to whatever you have.