Do your self a favor pic those rods pistons up if you wanna go threw the motor. How much are they hopfully under 350 get some arp2000 rod bolts. You can use the piston, but id get some CP's or Diamond. Those 03 pistons are fine for 550 all day long so people have made 900 on them it all depends on if it detonates. get 60 pounds if you want 500rwhp or more so you dont run them at to high of a duty cycle. As for stock they can take 10 psi for a while I see alot pushing 12psi without problem. Blowncobra on here runs 14psi he has had a s trim on his car for over 90k on a stock motor tuned by lideo car has 115k+. My setup should make somowere around 12-16psi I guess I will find out on the dyno, Iam hoping to last the summer then iam throwing manley rods and diamond pistons in it. If you want more then 450, Id step up to a ttrim to be efficant, and if its a procharger get a d1 dont waste your time on the p1 if you want over 500. I think that covers it