ok, i just got word from the machine shop that my ls block is out of round, different specs on each cylinder. so i'm glad i had it checked before spending my $$$ on the pistons. they say it needs to be bored over to .020, so i'm going to buy the pistons now knowing it has to be bored over so they can measure them before boring the cylinders.

here's my question, if it's going to be bored over .020, what mm bore is it going to be? stock bore on a b series block is 81 mm, so would this make it now a 81.5 mm bore? also, oem honda pistons are offered in a .025 mm oversize, what size mm bore is this?

thanks for the help.

 

Yah, .020 is .50mm, I don't think Honda makes .50mm over bore but there are copys of those pistons made by other companies. I'm not sure who makes them but I'm certain they are out there and they are not expensive.