Re: AAW wiring kit '70 chevelle alt wire markings.
I just did an AAW system for my 70.
Is your system an original wire harness or a Classic Update system? Mine is a Classic Update and the brown wire does go from the fuse box to the alternator.
I am using a Tuff Stuff alternator that is supposedly capable of operating as either a one wire or three wire, so I set it up as a three wire using the brown wire from the fuse box, what I noticed was a voltage draw when the engine was not running and the key was off. When I disconnected the plug from the alternator the voltage draw was gone, after speaking with the tech support at AAW, they recommended to just leave the white alternator plug disconnected and run it as one wire setup, which is what I am doing and it seems to work fine