The casting number is 7802644 tells you what you need to know.
http://67-72chevytrucks.com/vboard/s...33&postcount=6
"Not sure of my date codes.
I just ordered a re-manufactured box for a '70 chev.
Cardone 27-7501. Casting # 7802644.
Fits and works properly."
From this thread:
http://67-72chevytrucks.com/vboard/s...d.php?t=719663