charging system help!!

I need help with my charging system in my 68 dart. It has had the charging and ingition systems upgraded to the newer electronic . I recently bought the car and put a complete new wiring harness from Year One with the upgrades already in the harness. I canot get the car to stop overcharging like crazy. I have put two different alternaters, 4 voltage regulators all with the same result . I was told that perhaps it was a ground problem so I put two new grounds on the car. Still the same result. I am wondering if the original ammeter in the dash might be part of my problem as I am at my wits end!!