tag on master cyl. how to decode?

got what appears to be a new master cyl, 4 bolt that has a casting number of 3580121. also on little blue tag are the following numbers 1182, underneath is 5716a and sideways is pwr. pwr possibly for power? what does other numbers mean? thanks in advance.

Last 4 of MOPAR Part number, and 10000 day calendar date code.

thank you so much.

A 10K calendar date that low for this type of master cylinder would be years before this style was in use.

It is actually day / year format. 1182 = the 118th day of 1972.

Casting number may help too.
Mastershake may have more info.
He wrote this and is a member here.
http://www.moparts.org/Tech/MoparAction/Master_Cylinder.pdf

the casting number is 3580121, which cardone says it could be a 1 1/32 or 15/16 bore. are there any other numbers on it that may mean something to help identify itit without taking it apart? thanks.

Do not trust any information from companies like Cardone.
They are more than happy to consolidate different parts to sell something 'close'.
There were enough typos and errors in the original information, but compared to the aftermarket they are 100 times more reliable. Way back when, errors in replacement part info would be caught by various checks, and in the worst case the counterman and/or customer. These days, nobody even copy edits.

Since the folks above say its a '72 build, look in '72 or '73 Chrysler, Dodge, Plymouth Parts book.
My guess is the A may indicate replacement (vs. production line part).

You can download some for free from Mymopar, or buy a digital copy on CD.
Go to the parts illustration page to get the section number.
Then go to the parts list for that section number and skill through the master cylinders looking for one in which the last 4 digits match up.

Not the numbers for date code.

Interesting tag and may have error. The part number is 3580112 for this mc right? Tag should be 0112 and the other number is calendar date. Not sure why 112 and 8.

Maybe things changed on tags that were later over counter production.

I believe the first line is the last 4 digits of the part number.
1122 corresponds to a drum brake master cylinder part number and from the picture, it is apparent the part is a disc brake MC.
Bill Rolik is reproducing some of these tags
Bill Rolik catalog listing

I think your looking at wrong tag. The orig poster tag is 1822. The one I posted (not mine) is a 0122 which does correlate to a Part number for Power Disc for 73. Which is the same casting number as orig poster. Now may be later in 75 or 76 they had a new part number assigned that would have 1822 as last 4. Not sure. I don't have a part book that late.

I couldn't find a link to the page Bill has for his MC his tags on so just posted an example of one he sells. But he explains the information on the tag in the listing for a reference to the topic here. I don't see that he lists one for 1182 but the format shown in the example should be the same. I see I had a typo in my post 1122 instead of 1182, but 1182 would correspond to 3461182 which is a power drum brake MC for 71-72, which doesn't look like the MC shown in the OPs picture.

Any cross ref for the casting number to the p/n it was used for ?

i looked at 72 parts book that i have and it shows 3461182 as r,p,d body. i will look at 71, 73-76 books when i go out side. also casting number is 3580121

It is easy to move a tag over. If this is not NOS out of a sealed box, and even then..... maybe someone mixed tags up at some point.

I meant my question about the casting number cross ref for Mastershake.
Was quoting your first post with casting numberso he would see the number you posted.
Sorry about the confusion.

On a spreadsheet I've been compiling p/n to castin numbers I've got casting 3580121 as used for p/n 3580112.
Used for A-body, 1973-74 Power disk brakes with floating caliper. 15/16" bore
Looks like that came from Paul Herd's book, and no verification that I can attest to.

I'm surprised I had that, and so far the information lines up with what you have.