A dial caliper is fine for determining if a block has already been decked. But for something more precise, installing the entire rotating/reciprocating assembly and checking every piston not only gives you a figure for the deck height but insight into how uniform the final rod/piston length is for each cylinder. I mean in the end, what are you really trying to accomplish, a certain deck height (crank centerline to block face) or a desired piston height (piston crown to block face)?

"We live in a time when intelligent people are being silenced so that stupid people won't be offended".