charging problem

I've started getting high voltage following higher engine rpms. At idle I have 14.3 volts and at high rpms it's as high as 15.5. This is checked with my dash mounted volt meter and a digital multimeter.

I changed the voltage regulator and got the same readings.

I checked your test out and have a few questions. I freely admit that the charging system is one of my weak points so be gentle. No ego here. I am a dumbass on this.

First off can you explain "voltage drop"? When I think of voltage drop I think of losing voltage due to resistance- for instance by a poor connection or a long distance over a wire. How does this test check "voltage drop" in the car?

Below are the results of the first set of tests you outlined:

On the first test I connected to the dark blue field wire at the alternator and the positive battery post with the ignition switch to "running" and the engine off. With the meter set to DC voltage I got 12.56. Pretty much straight battery voltage.

To test the ground circuit I'm assuming I need to switch the meter to read ohms now because I'm reading from one ground point to another?

With the meter set on 200 ohms it was .9 when I first hooked it up.
With the engine running fast it was .8
With the headlamps on running fast it was 15.0

I ran a 10awg jumper wire from the negative battery post to one of the regulator mounting bolts.

1.0 engine running fast
12.3 engine running fast with headlamps on.

The final running charging voltage test was the first thing I did as you saw above.

What do you suggest next?

I followed that wire coming off the regulator ignition terminal on my factory wiring diagram and through a couple of splices it kind of goes all around.