check the tolerances in the cylinder and your used pistons to accepted values= solves your problem.

The reason(IMO) for suggesting larger pistons is that you are completely safe in regards to tolerances and rings sealing properly (w/ a good break in). Your pistons have slowly been wearing away minuscule amounts of the cylinder walls and themselves..prob an amount so small it doesn't matter. Although, it might just be enough to wear even new pistons won't work as reliably as a bigger size.

 

ok well the motor should be pulled in about 3 hrs or so from now... after i check maybe i will just go with the 87.5 size