Cuda overcharging? Please help...

If you've checked all of the grounds, move to the power side of the equation. My earlier post was trying to explain that there are 2 things that could cause the same symptom.
Pick up a cheap multimeter and with the engine idling check the voltage at the line that runs to the regulator, then check voltage at the battery. I'm not sure if it's the blue or the green wire (think its the blue one). A further test would be to put the negative lead of the meter to the chassis of the regulator then put the negative lead to the negative terminal of the battery while keeping the positive lead tapped to the input wire. If the voltage changes you have a ground issue. The input should be the same voltage as the battery is getting. My guess would be that the regulator input voltage is lower. It's not uncommon for a corroded system to lose 3+ volts. The reason for the voltage drop is that the regulator gets its power through the ign circuit, which runs from the battery through the bulk head connector, through the ign switch, back through the bulk head connector, and so on. ( please don't use my memory as a wiring diagram :lol: ) It's easy to see that if each connection only dropped .5 volts due to corrosion, the regulator is operating on bad info
My car had the same issue when I first got it on the road, ended up being a combination of marginal ground and low input voltage. Electrical issues can be time consuming but a methodical approach with a wiring diagram and a volt meter is usually better than swapping parts like I started off doing