Having started racing 71 and 72 340's in stock eliminator back when stock factory pistons were required I have a few sets. The 71 pistons at blueprint specs were .045 above deck with an .028 gasket and had 2 valve notches.The 72 and later pistons were .054 down in the block with a .032 gasket and 4 notches. With the 71 at specs and the head at 63.3 cc's the eyebrow above the intake valve would kiss the piston and the valve notches were not deep enough for the cam. It took some massaging to get everything to fit.