I'm looking for factual information on how much a b16 can be over bored and still be within maximum tolerance for boring (.040" over? .060" over?) Also, does anyone know how large JDM p30 pistons go above standard size?

 

there isnt a black and white, its a shade of gray. honda will only sell you .25mm (about .010") oversize pistons for most engines and i think theres one that comes in .5mm over if im not mistaken.

aftermarket manufacturers will sell you anything you order. how long it stays together depends more on the tuner than on the cylinder wall thickness. jeff evans has made 650 whp on stock sleeves several times. other kids cant keep a motor together at 200. i dont think 82mm is unreasonable for a stock b16 at all, i wouldnt even hesitate on that longrod/shortstroke motor.

nippon probably makes a p30 copy in various sizes, check ebay. i actually think the nippons are great for the money.