Need help with date codes 742 - 8 3/4 center section

Dana67Dart · Feb 27, 2018

I'm looking for a 742 center section and have seen many available. I would prefer to get one with a date code in mid to late 66 or Jan 67. I can't for the life of me figure out the date codes. Some have 3 or 4 numbers, some have number-letter-number-number. I have searched google for a definitive answer and have come up with the following:

7M13 = 1967-12-13 or YMDD with m=12 (no use of "I" in the code) from a website explaining
6031 = 1966-31st day of the year (my guess from other date code websites)
These two make sense

But what about:
6P17
5U22
232
M12 (741 case)

What am I missing

crackedback · Feb 27, 2018

Why?

If you are building a 100 point show car needing gold certifications, knock yourself out. Building a driver hot rod... find a good case and build it if that's the case you want.

The 741/489/742 strength stuff is way overblown regarding any weakness. The pinion bearing is not the weak point!

Dana67Dart · Feb 27, 2018

crackedback said:
Why?

Because!

All kidding aside... I don't know. I'm not into numbers matching though my dart is, but there is something fun about finding the right part that could have been on from the factory. Example. I bought a 4V cast iron intake, would have happy if it had been 66-69, it turned out to be late 66 and a California emissions casting number. Dart is a California car built feb 67 so the intake is the perfect fit. It just gives me goose bumps!

I know I have a problem!

oldkimmer · Feb 28, 2018

There will be a date on the crown gear that is easy to see and read. Kim

Dana67Dart · Mar 1, 2018

Thanks Kim, Unfortunately most of the cases I'm looking at don't have gears and most of the ones that do don't show that part of the ring gear.

I'm still baffled by the date codes, unless they are not date codes but some other casting mark that is screwed into the mold right under the part number on the drivers side.