SB2.2 Head Info

[fabr]

I have a set of Hendricks SB2.2 heads with DH11C on the end with these additional numbers on the end. 06-R just under the DH11C and above ,to the left is 28J6025 on one head and 28J6029.
Any info on these heads as prepped by Hendricks would be appreciated. Thank you.

[Schurkey]

Possible to contact Hendricks directly?

[fabr]

I don't know but WarpSpeed answered my basic question on another forum.