I did it to a 73 Cuda. The mounting ground was sufficient for the RT regulator. Just hooked the octopus to the gauges on the stud and 12 V connector on to the blade. Has been installed for over five years now with all gauges reading properly.
Craig

2014 Ram 1500 Laramie, 73 Cuda
Previous mopars: 62 Valiant, 65 Fury III, 68 Fury III, 72 Satellite, 74 Satellite, 89 Acclaim, 98 Caravan, 2003 Durango
Only previous Non-Mopar: Schwinn Tornado