Am i safe to bore my cylinder walls to run 81.5mm pistons? I read somewhere that boring out the walls can make the stock sleeves weaker, looking for 350-400whp. I think i found a killer deal for 4 cp forged pistons for 150 locally so im thinking of snatching them up.

 

you're fine at 81.5

 

81.5mm is perfectly fine.

 

A guy pulled these outta a b18c5 and im putting them
In a b18b1, makes no dif cause the cylinders are the same correct?

 

compression will be a little bit lower, since you have a bigger combustion chamber (if using ls head). but it will work.

 

will be in a ls block and gsr head. They are stock compression, 9:5:1 with gsr head (the guy told me this)

 

Are they second hand? Or new?

 

Used

 

Have you weighed up the cost of the pistons and a new set of rings against a new set of Supertech pistons? I never recommend buying used pistons. You don't know what they've been through.

 

400 for supertech pistons and rings. 140 for these pistons plus another 60 for rings.

 

Thats not a bad price for the rings. They normally cost me a lot more than that but i'm from the UK. I you honestly think you can trust the guy then go for it. Bear in mind what i said though, you reallly don't know what they've been through...