Be aware that the blocks are usually .015" or so higher than what they quote, and the piston height above deck [blueprint spec] as I remember it was .045". So in the real world the early 340's used to have around .030" positive deck height allowing for the extra .015" in block height. That's what I have found when checking piston heights in factory engines as well.
This is correct, but that is with a shim gasket. You must ass the extra gasket thickness to the positive deck height.
I've run them over .060 out with no problems.
