Early '67 Power steering box

[MyRed67]

  I am currently in the process of doing a complete restoration of my Early (no holes in frame horns)'67 Sub-frame.  Today I was cleaning up the Power Steering box, so I have some #'s for you if you're interested.   The car is an 11A (66) LOS built.   It has (according to your report the correct;   5691676 casting.  It has a 266 casting date, on the cover it has 276 6 (I believe that is actual build date?)(and would be 276 day of 66?)   Which I believe would be correct for the 11A build date of the car?   There is a 13 stamped under the 5691676, I'm not sure what that means.   I hope this info. is helpful.