The 3917124 was used in late 67 as well as 1968 and early 1969. The ID code "CI" was used in all three years for a 3.73 Postraction so that's not much help. As suggested, look for a date casting in one of the webs like this:
You'll have a letter for the month (A...L for Jan...Dec) followed by a 1-or 2-digit day of the month followed by a 1-digit letter for the year. This example is June (F) 21, 1967.

You'll have a letter for the month (A...L for Jan...Dec) followed by a 1-or 2-digit day of the month followed by a 1-digit letter for the year. This example is June (F) 21, 1967.