PCV valves

I understand that PCV valves are sized to the amount of vacuum your motor makes. Stock cars having 18 - 22 psi of vacuum. I'm looking for a PCV valve for a motor that makes 6 - 8 psi of vacuum. I understand that there is a book that has this info. I
need the part # for the ford and chevy engines. I think because my vacuum is so low my PCV valve might not be opening all the way causing higher than normall crankcase pressure. PLEASE HELP!!:CRY:

With a motor making that low of vacuum, pcv valves may be a bad idea. I would reccomend a breather. That way you dont have to worry about pressure in your crankcase, itll just be open all the time. Best of luck!