Cartouche (top-left) is also Khufu (written vertically). The cartocuhe (top right) I believe is a variation of the name of Shepseskaf.
The text reads:
"Cartouches in tomb to the W. [west] of first pyramid are different than Suphis [Khufu]."
You might find this thread of interest.
Post Edited (16-Jul-14 11:44)