I am looking for somebody who can tell me if the alt. light 70 chevelle has any significance on the charge system, and can the brown leed in the harness that goes to the light, be used to connect to an autometer volt gauge wthout any other modifications. I would appreciate any help on this subject.

I believe the alternator field winding voltage goes through the bulb. There is a resistor in parallel with the bulb in case it blows you'll still have voltage to the field windings. The volt gauge should be connected to a switched 12v source in the fuse block and ground. Some people prefer to connect it to 12v at battery or horn relay. All depends on where you want to read the voltage. Voltage can be a little lower at fuseblock, due to voltage drop, depending on what accessories are on, but is still a good location. Under the hood location is not switched so guage will always be on, not much drain on battery but some.