how to read head codes?

i have 2 z6 heads here and id like to know what they came from the first code is
1#
p08-4 on the right side of the stamp is 9/4
2#
p08-6 and on the rs is a 9/2 stamp
i found a bit of info on google but none thati found to useful
1#
p08-4 on the right side of the stamp is 9/4
2#
p08-6 and on the rs is a 9/2 stamp
i found a bit of info on google but none thati found to useful