[Mr70]

Where was your Chevelle assembled and on what date?
Chevelles built within the first 5/6 mos.of production received 2pc. rotors.
1pc. rotors became the norm within the months following that.
Jan/Feb.70 seems to be the changeover date,but with 7 plants building them,there were variations among them from what I've seen.
The steering knuckle code in box #12 on your buildsheet helps denote this,as well as the backing plate used.