Like said. "deck hieght" is the distance from the crankshaft centerline to the flat surface of the block where the head mounts. You add up 1/2 the stroke (3.75/2= 1.875), the rod length (6.768), and the compression hieght of the piston(2.061) and total it up . that's 10.704. Deck height on 440s is supposed to be 10.725, so they should be .021 down from the deck on a blueprinted block. Only, like CP said...they are never at 10.725 unless they were decked once already. So you may need more decking than .015. Your machine shop better be able to tell you what height the block is now...If they can't, dont let them rebuild your engine.