i am about to build a B18A and i have decided to have to block bored, i was worried about the sleeves strength. 10 or 20 over? what is your opinion, or should i do something else? 10 over i hear alot but others say that 20 over will give me a a straight clean bore all the way through. i need opinions asap so i can order my pistons to have them fitted properly

 

.020/.5MM over is the more common size. Just get that, I don't know too many OTS 81.25MM pistons.