0 psi unless you want to build it. you can boost maybe 7psi daily maybe 10 at the track. but aith a stock c/r of 10.8:1 i dont think you would want to go much higher than that. you woudl have to get a really good management system. a kit liek greddy or something would pop the motor you gotta have injectors no fmu i woudl do a stand alone. if you wanna do a kit you should build the bottom end head can hold about 15psi but the bottom end nah. build the bottom stroke it, open up the bore. forge everything and boost thepiss out of it.