Hey Rick, Check out this thread. The option is z62. Longhorn Man posted this 6 years ago. It's in the faq section. I understand it took him 1 1/2 hours to type in. So a shoutout to Andy for that. It's from a gm 67 restoration catalog and in about 5 min of reading your going to be a expert on standard and optional equipment and the codes. Hope this helps.
http://67-72chevytrucks.com/vboard/s...d.php?t=121155