Charging Issues Mechanical Voltage Regulator

Finally converted my 67 Cuda from points to electronic with a Promorm kit from Jegs. New distributor wiring harness and orange box. The first unit had no fire, so installed the second one with now problems. Engine starts easier and sounds crisp.
Noticed that my ammeter is not showing a charge, even when the engine speed increases. Voltmeter confirms only a slight charge ( 12.5 volts ) when the idle speed is increased.
Tried adjusting the mechanical voltage regulator, but now I am confused.
It either doesn't charge at all, or with an adjustment it wants to overcharge..15 volts or more at idle and increases to 18 volts as the idle goes up. Battery is fairly new, as is the alternator.It's a one wire alternator, and all of the wiring and connections under hood have been inspected and ohmed out.
Not sure where to go...any help would be appreciated. Larry