The other thing is to use the right PCV valve. There were 4 valves I tested when I was doing this. Two were worthless as they allowed too much vacuum pull-through. Two were ok, but one clearly was the best in my opinion and one only allowed a bit less than 1 inHG. Unless you're mounting the PCV valve too low, I don't think 1 inch is enough. I'll try to remember to post the make/number of the one I used...probably should have posted that here, but didn't. As I said above it is sort of a balancing act. You need to check the valve after you have everything in place to make certain it is doing what you want.
