Numbers on the bottom of my block

[bull]

I found this stamping on the left rear bottom of my block: PT383R22850277. What does it mean?

[Ghoste]

The "PT" means Trenton assembly plant, the "383" is the cubic inch size, the "R" I don't know, the "2285" means it was built on Oct 30th, and the "0277" means it was th 277th engine they assembled that day.

[bull]

The "PT" means Trenton assembly plant, the "383" is the cubic inch size, the "R" I don't know, the "2285" means it was built on Oct 30th, and the "0277" means it was th 277th engine they assembled that day.

Ok, so that raises more questions. How is it built on Oct. 30th if the cast date code is Aug. 67? Does this mean the block casting date is August while Oct. 30th is the assembly date?

Trenton? Did the Trenton engines go to Hamtramck?

[Ghoste]

Yes, the casting date and assembly date are two different things and one obviously must precede the other.  Yes to the other as well.
BTW, that assembly date is for Oct 1968, just curious but your block was cast over a year before they used it? 

[bull]

The engine casting date is August 1967 and the car was assembled and sent out the door on Jan. 8, 1968 according to my fender tag. It makes sense to me then that the engine must have been assembled in October of '67. How did you get the date Oct. 30, 1968 out of the numbers 2285?

[bull]

Ok, here's what I came up with after some research. The 'R' appears to stand for Regular, as in regular gas. PT is as you say, Trenton. 383 of course means 383 ci but I think you are mistaken about the 2285 number. It appears to refer to the julian 10,000 calendar and I found a link to a site where a guy says the julian date on one of his componants is Dec. 29, 1967 or 2345, which therefore puts my engine's assembly date at about October 29, 1967 when you subtract my 2285 number from his 2345 number, assuming my math is correct.

Here's his julian date quote and the link:

"On this side of the transmission, you will find the assembly plant code, part number, 10,000 calendar date, and the build sequence number-per day. The part number on this one 2801541 was used on 1967 and early 1968 440 HP engines. The 2345 julian date equals December 29, 1967. This corresponds with my 68 R/T's build date of January 12, 1968."

http://andy440.com/other.htm

[John_Kunkel]

The Mopar date codes are often expressed as a "Julian date", the 10,000 day date code isn't the same as the Julian date; the 10,000 day calendar has a random beginning and ending date when compared to the Julian or more common Gregorian calendars which are based on the time of year.

[Ghoste]

I used a 10,000 day calender but I was using the one for the 1968 model year.  I took it to mean calneder year 1968.  Sorry Bull. 

[bull]

The Mopar date codes are often expressed as a "Julian date", the 10,000 day date code isn't the same as the Julian date; the 10,000 day calendar has a random beginning and ending date when compared to the Julian or more common Gregorian calendars which are based on the time of year.

So if it has a random beginning it basically means nothing, correct? Which is this number, Julian date or the 10,000 day date coding?

[69CoronetRT]

The Mopar date codes are often expressed as a "Julian date", the 10,000 day date code isn't the same as the Julian date; the 10,000 day calendar has a random beginning and ending date when compared to the Julian or more common Gregorian calendars which are based on the time of year.

So if it has a random beginning it basically means nothing, correct? Which is this number, Julian date or the 10,000 day date coding?

It's not a random beginning. It has a start date but that date can be any date of a Gregorian calendar. A 10K calendar allows you to express ten thousand calendar days in only four numbers. Say you started on 1/1/61. That would be 0001, 1/2/61 would be 0002. The date 0365 would be 12/31/61. 1/1/62 would be 0366 and so on.

You could have the 10K date start on any one day of the year. That's what John means by random. You could start a production calendar 8/1 to coincide with the start of a new production year. You could start it 7/1 at the beginning of a fiscal year.

So we get up to October 30, 1967 that's day 2285 in the 10K day calendar.

I don't know the actual date that Mopar used for day one. I just used this as an example. You could figure it out by going back 2284 calendar days if you really want to know. Just don't forget to account for leap years.

[bull]

I think I'll go with that one rather than count backward 2285 days. It's got to be after August 67 since that's the casting date. October 30 is as good a date as any.

[dstryr]

You can find a 10,000 day calendar converter here.

The Chrysler 10,000 day calendar started on July 29, 1961.   

[John_Kunkel]

It's not a random beginning. It has a start date but that date can be any date of a Gregorian calendar.

If it can be any date on the Gregorian calendar it is "random" by definition.

[bull]

You can find a 10,000 day calendar converter  here and  here.

The Chrysler 10,000 day calendar started on July 28, 1961.   

That second link takes you to a calculator that works.

I found one of those calculators (just like your first link) on another site and like this one no matter what number you punch in you get Jul 28, 1961 as your answer.

[dstryr]

Thanks, bull

I had always thought that July 29, 1961 was day 1 but the first calculator said differently and I didn't check it with any other dates.  I'll fix my post. 

Frank