Just double check when you have both in your hand.
Not “kinda” the same length...... but the same length.
I would think in order to get any 318 pistons near zero deck height, a fair amount would have to be cut off the block........which would generally require shorter pushrods.
Maybe there’s some piston where that isn’t the case.
Can you ask the machinist how much was cut off the block?
Has anyone verified the lifter preload is correct?