Where is the casting date on a Mopar Performance Crate 360?

[Kern Dog]

I'm helping a friend and while tearing down his MP 360/380, I can't find a casting date anywhere on the block. The B/RB and LA blocks had it on the RH/Passenger side but this one does not have anything resembling a date on it.

 

[Bobzilla]

Check out post thirteen in this thread:

360 Magnum production date question

 

[Kern Dog]

There is really nothing special about any Magnum block until you get into the Mopar cast iron race blocks, but those should identifiable with a casting number starting with a letter P and will have the large letter R cast into the front of the block under the passenger side head deck surface.

Your casting number is typical of 5.9 Magnum engine blocks. The Date on the right side everyone keeps mentioning was easy in the old LA blocks because it was a conventional calendar date like you would normally write on a check. The "date" on yours may be a julian date instead of a calendar date. I am not sure. but there is a pad on the front of the block under the left cylinder deck surface that should have stamped numbers. That will tell you more info about what your block is, or what it came from. I will attach a chart below.View attachment 1716312830

Thank you.

 

[Kern Dog]

"Julian date" is one that I'm not familiar with. I've only heard the term in passing but never asked nor was told what it is exactly.*
This engine did have a series of numbers and letters under the LH head, they were in a place that seems stupid when compared to the traditional methods where anyone that went to grade school could interpret it.
This number didn't have a T for "truck" but one character was a "1" though I don't know if that was a 1991 or 2001. Did they make the 5.9 engine in 1991?

 

[Kern Dog]

Here are the stamped numbers....

1 N K ? 1991 or 2001?
N K.... I don't see an N defined anywhere but the K could mean Toluca.
5.9L, self explanatory.
1361 = what? Is that the "Julian Calendar thing?
The rest on that line is 1 205A, the bottom line is 469.

Rich and I took the block in to the machinist today....It was standard bore! I thought that ALL of these Mopar Performance engines were at least .020 over. The "1" in the number makes me wonder if this is a 1991 block, the very first of the "Magnum" series engines.