Other than the stamping on the rail is there any difference externally of a HEMI 727 vs. a RB or b 727?
I know the pan rail should read:
xx 3410671 xxx xxx (for a 70 unit)

Was the HEMI unit only made at one plant location?

All automatic trans back in the day where made at one plant - the Kokomo Trans Plant.
There are no external differences between a big block and hemi 727.

As I suspected. Now what is the prefix for the Kokomo plant in the pan rail number sequence? I see one with a J xxxxxxx and one with a PK xxxxxxx

PK

So what is "J"

Never got a good explanation for all the strange prefixes and suffixes after the base part number - but all of these transmissions should have had a PK in front.
I can't confirm a story I heard but some units were shipped in pieces then "built" at another location - but that has never been confirmed.
The suffix after the part number may have something to do with the line that built the unit.
The plant so many transmissions that is is likely to have had more than one line - or shifts - and the alpha may be for tracking line or shift.

Only a few people are alive that still work at the plant - they may know the real reason.

Thanks I appreciate it.

The transmission Dip stick tube is unique to a Hemi Transmission.

Someone opined that this means it is a parts room replacement built at a date later than the model year.

The example below is for a '67-'68 model year but the build date is mid-'72.

I have ran into the question of date before where some were dated with the normal 10,000 day calendar. But have noticed that 67 and back the date doesn't seem to be the same. I have a 67 440 HP trans and I believe that it stamped H for the plant, then the part number, followed by the date. but the date is not correct for the year. I have seen them stamped PK, H, and J before the part number. Would like to know more on the dating as well. I can try to get pictures maybe later, if that helps.
Matt

there is some discussion of non-"PK" transmission part numbers '62 auto trans - on MOPARTS

Here is a picture of a 1966 hemi 727 that is still attached to a very unmolested 66 hemi engine. The engine appears to still have the original fan belt and a M embossed mopar oil filter on it. It was supposed to have been pulled and shelved in 1969, so I have no reason not to believe it is factory original like the rest of the engine.
Matt

Another interesting thread about dates.
https://board.moparts.org/ubbthreads/ubbthreads.php/topics/2255708/727-identification-help.html
Matt

Ok here are a few of some personal transmissions that I have. 2 are from 68 cars. Both are stamped PK with the part number and dates that look to be the correct 10,000 day calendar. One being a 68 hemi 727 that has a partial vin stamp, and the other a 68 904 unit.
A couple others are from 1967 year cars both stamped with H and part number. One of those is for a 67 hemi auto H2801544. I bought the trans from a guy who said he pulled the engine and trans from a running car 35-40 years ago, and he only sold the engine and stuff a coupe years ago.
the other is a 67 440 HP trans a H2801541. The trans with the H plant stamping has the strange dates that would not be correct for the normal thinking of the 10,000 day calendar, but it is the same as the 66 hemi trans pictures that I posted earlier. Maybe we can figure this out.
Matt

Interesting. What I am looking at reads:J2801540 4245682
Which indicates:
j - ?
2801540 - 67-68 440 C body
4345 - Build date of March 12, 1973
683 - ?

Maybe I’m wrong but I believe we are not interpreting the date correct. I don’t think they would be building and stamping a 67 trans in 1973.
Matt