I got endyn b18b FI pistons, and i just finished breaking them in and my compression results were 190-185-185-190. My problem is, endyn' website (http://theoldone.com/components/pistons/) says those pistons have a c/r of about 8.84 - 9.21:1. 190psi seems kind of high for that range. I dont kno if my piston rings have fully broken in, i have 200 miles on them. I'm guessing they are.