My deck isn't square to the bore. The bore could be off but I don't think that's it because I checked the distance from dowels to oil pan rail and that dimension is off the same direction. If I had leveled to the dowels my piston would rock proud .015 on both the quench and opposite sides instead of .018 and .012.
Checking the deck height in the center eliminates skirt clearance from the equation. Then deal with the skirt clearance as another variable.
I expect the piston rocking to be less at operating temperature when the forged aluminum piston has expanded more than the iron bore.
