HELP! charging system BLUES

Your battery should have a static charge of 12-12.5 volts so if you are seeing 10v anywhere in the system YOU HAVE A PROBLEM!!! A 2v drop between the battery and the ignition switch is way too much. You are just turning that current into heat somewhere. I agree that you had better take a look at your firewall connector. Also clean both ends of the positive battery cable, body ground, battery to block cable and engine to body ground points.

Now, with the engine running at fast idle, you should be getting 13.5v at the back of the alternator. You should be getting close to that at the battery as well. If you do bypass the ammeter (not a bad idea) you might want to consider bypassing its wiring through the firewall connector. Running at least a 10AWG wire from the alternator output post directly to the positive battery cable on the starter will suffice. If you plan to add high power headlights or a monster amplifier, you want to drive them from here too so their current does not have to go through the dash