cleveland fuel pump bolts are horizontal, not vertical. I just swapped fuel pumps on ours over the weekend. Post a pic of the engine.
wait a minute, by vertical do you mean the bolts go thru the pump at the 12 and 6 o'clock positions? If thats the case, then yeah, it might be cleveland. By vertical, I thought you meant the bolts actually screw up into the block, rather than thru the side. Windsor pumps have bolt holes at the 3 and 9 o'clock positions.