Clarification on Exhaust Manifold date codes and those without dates

[Bossgold]

Ok, by all accounts the date codes should read as julian dates so 3189 should be Nov 14th, 1969....and Not Mar 18, 1969 on exhaust manifolds. the 0179 and not 10179 as it looks in the picture is 17 day Jan 1969 - see pictures. Then here is where I am stumped...I have AAR manifolds that came from my car with  the correct casting numbers of 2863549, & 53  but no date codes anywhere except and L1 & L3 below casting-the same as this picture. I am almost certain they are original....or am I wrong ???? Do all 340 HP manifolds have date codes on each side?  If I need to replace with date coded manifolds is it 3 months out ( so Build is 3-20 therefore dates Dec 69, Jan 70 would be correct)?

Thanks in Advance

Linkback: https://forum.e-bodies.org/cuda-and-challenger-general-discussion-roseville-moparts/2/clarification-on-exhaust-manifold-date-codes-and-those-without-dates/10090/

[750-h2]

Bossgold . Can you explain to me how Dave Wise gets a casting date of October/19/1968 on this manifold. I just cannot figure it out.

[6bblgt]

it is typical of AAR & T/A timeframe 340 exhaust manifolds to have the embosed part number "toward the block" manifolds

all the rest of the above manifolds have a month/day/year date format

2863549 (my 1968-‘70) 3189 = TUE. 3/18/69
2883549 (my 1968-‘70) 10179 = FRI. 10/17/69
2843992 (my 1968-‘69) 91168 = WED. 9/11/68
 

[Bossgold]

6bblgt - 'it is typical of AAR & T/A timeframe 340 exhaust manifolds to have the embosed part number "toward the block" manifolds'

so to clarify - 1970 AAR Exhaust Manifolds have no date codes just the casting 2863549, 53 and an L1,L2, or L3 facing in toward the block?

- These  date examples you gave  -   Do Not follow a typical MOPAR Julian perpetual Day calendar i.e. 318 th day of 69 but instead what was listed below

2863549 (my 1968-‘70) 3189 = TUE. 3/18/69
2883549 (my 1968-‘70) 10179 = FRI. 10/17/69
2843992 (my 1968-‘69) 91168 = WED. 9/11/68

thanks for the help cause the answers differ depending on different theads in forums.