[rotorwrench]

I've always figured that 1/8" is about as thin as a person should go when calculating to a bore job. Some sleeves are 1/8" and some are as thick as 3/16" and in some cases the sleeve is about all that is left to repair a corroded, cracked, or a bored through cylinder wall. A good ultrasonic check of thickness will give a general idea of how much corrosion there may be lurking in the water jacket but it can miss some spots even if a tight grid pattern is followed. This is all if the block didn't have any issues with core shift during the casting process.