Isn't that the reason for un-grounding the brushes?
Just to clear up the grounding and underground............
70-79 has a B type charging system
80-83/4 has an A type charging system
The 80-83/4 SS combined reg/rect, (A type charging system), can be swapped into the 70-79, (B type charging system), by isolating the ground brush and energizing it of the brown power wire
Aftermarket Automotive Regulators can be bought as an A or B type .................... there is no need to change the brush system on your factory original Stator if you buy the right Regulator for the right system.
There are Combined SS Reg/Rect that can be bought for the 70-79 points system, (B type), charging system.........Buying automotive regulators and a 3 Phase rectifier can save quite a bit of money and have been found to be more reliable than some of the cheap SS Reg/Rect