I have one of the original p600b's with the 9# pulley. Since then ATI dropped boost to 8# on their standard p600b kits. I'm in the process of building a 383 and am wondering if that kit would be up to the task of supply a freer breathing motor? The instructions state that the kit was designed for a stock lt1 motor. Would it be necessary to upgrade to a P1? I'd hate to have to sell this kit to purchase a new one. Is it possible to just buy a head unit?

 

I would ask first, what are your goals for the motor. If you put a 12-15 psi pulley on the p600, you would start to get to the max rpm that the blower can handle. But if you just wanted a little boost on the motor you would be good. Just don't forget that even though the boost gauge is telling you you are pushing 5 psi instead of 9(or somthing like that), the amount of air being pushed is much great than the 5psi that you saw on the stock 350 setup. I would say just don't rush in to get a new blower because others say you need 10-12psi etc. If I remember right the old p600 is the same model that they used on the some of the early big-block carb setups. Just my 2 cents. You never know, what your motor can pump out. People still have a hard time believeing me on the numbers that I put down when I did my dyno tune. You might just be surprised on what the p600 can do. But as a true HOTRODDER, if you go the money, Bigger is always better, and to much HP is not quite enough!