[Mr70]

Among the Chevelle Clubs and restorers,it has been documented as being done both ways.Plant and time period did not seem to be a factor,so it is considered correct either way,on 1970 Chevelles anyway.
I have pictures of engine compartments from 1970 showing two Kansas built Chevelles with ground in both locations.
I have seen cars grounded at the Head,but carrying Alt.bracket with a threaded hole unused.
This will always been argued between Owner & Judges.