Hello, I just picked up a starter for my Challenger and I'm trying to figure out the date coding. it's a 3 digit code "190" which I'm guessing is the 19th week of 1970. If this is correct, how were the weeks assigned? For instance, the first week of 1970 only had 3 days in it: Thursday through Saturday. Was it those 3 days that were counted as the first week, or was it the first 7 days and then the next 7 days from where that ended, or some other way?

I'm taking it that is off the field can which you would be correct but there is also on the casting the date wheel that should have a 70 in the center of the wheel. The dots in those spoke'e of the wheel is the month so there should be at least five spokes with dots since that is a late April date. A rule of thumb the field can date should be before the casting date? If there is on dot in the let say in the fifth spoke that would be the first week of May your field can is the fourth or maybe the fifth week of April.

Correction looks like the 19th week was the week of May 10 for your field can. So casting would be after that with at least five or more spokes with dots in them.

more info here

http://www.plumcrazygarage.com/Tech-Info.html

Thanks for the help, fellas!