Close up shot of cylinder walls. YES, these are the STOCK bore size, opened up .003" more to accommodate the expansion characteristics of the forged pistons at wide open throttle (when HOT!) - they cleaned up beautifully with the Lisle 15000 Pro bar type hone (most definitely not just dingleberry honed). These pistons are "talkative" when cold, but just right when hot. The piston rings were set on the loose side of the end gap range to accommodate Nitrous (150-175 plate system).