Normally bores wear more @ the extreme top of travel and do not wear round and different bores in the same engine will have slightly different amounts of wear--this is really noticible when boring cylinders as the boring cut is concentric with the unworn part of the cyl and some parts of the cyl are "cleaned up" before others.Many the front cyl will wear more than the back-I think because they see the cooler water from water pump and TOO cool running promotes cylinder wear.
Ever bore one with a torque plate on it and could that play a bigger role than temperature?
