newb block number question (318)

[iw378]

There is a bunch of numbers stamped on the front of my block drivers side just below the head. Noticed them while chasing an oil leak from the intake.
PM 318R 31990975. What do they mean ?
1969 barracuda if that matters

 

[TrailBeast]

http://www.rosevillemoparts.com/reference_castingnumbers1.php

 

[OldmanRick]

Do you think it could have been replaced at some point in it's life?

The "3199"0975 looks to be a build date of May 1st, 1970. And the 3199"0975" says it was the 975th unit built that day.



P.S. Are your timing marks on the pass side or driver side? Won't guarantee anything, but still would be info that could possibly help.

 

[EL5DEMON340]

The p should be the year, g is 71 so not sure about the p. The m is mound road plant, and the r after 318 is regular fuel as opposed to p which is premium .