Those are machined for 59 degree tappet angle, oil through the decks for offset drilled blocks and rocker shafts and 18 degree valve angle. Looks like it was cast in 1997.
I have also seen those castings machined for 48 degree tappet angle and for castings made starting in January 2002 for T&D or Jessel rocker systems only (no drilling of the deck for shaft oiling and different pedestal height and bolt placement).