55psi of boost?! Let me know how that works out for you...I was actually referring to the static compression ration of the piston, like if you wanted it to be 8.0-1, 8.5-1, 9.0-1 and so on. If you are using flat top factory pistons, that would leave you with a high compression ratio depending on what components you were using them with, but if you are getting straight up aftermarket pistons, the manufacturer should be able to tell you what the CR is going to be with that piston.