Did you ask the person you bought it from why the head was off? He pulled it for a reason and left it that way for a reason.
I am not knowledgable with OBs so cannot give much advise however from the picture it's the outer wall missing so I do not think a sleeve will work but I shop can tell you. BTY it's hard to tell but the cylinders look rusty which may damage the rings in the other cylinders.
Starbrites extreme clean works well.
1997 2400 SCR
5.7 Vortec / Bravo 2