I couldn't find YE for '68 either. The crank code matches up to a late 67- early 68 400 Nodular. All the other numbers for the block match up to '68 400. Maybe he is wrong on the YE. Kind of odd with YE but is it possible it was a late '67 YE 400 block that slipped into '68 numbers? I don't know how they manufacture those blocks.
Pretty good deal on price IMO except for the drive. But we do what we have to do to get a correct year block if we don't have a good option locally.
I hope everything works out for you.
"An ignorant man thinks he knows everything, a wise man knows he doesn't."