well 450 to 500 and u might crack the block, i posted up a thread about this like 1 month ago, a lot of people suggested i get ARP head studs to help out with the boost, and DEFF buy a very good FEL Pro head gasket, thicker and stronger. And then it really comes down to a great tune and just running safe levels of boost, see its not the engine im worried about blowing, its the drivetrain thats why i plan on calling up promotionpowertrain.com and getting a nice built tremac,ligthened flywheel, super king cobra clutch,aluminum driveshaft, and eventually built the rear end