Have a smog system from a 1968 z28. Taken off by the original owner in 1968 w less than 500 miles . Sitting in his attic for 44 years until last month. has a shallow groove pulley,nothing is altered,modified or ever changed. I have read that others[including one person that took it off when new] have seen this,was there a time frame when it may have happened? Pics to follow