I run the system as advertised and it runs perfectly. Has nothing whatsoever to do with idle, rpm, nothing.. all it does is clean the bad gasses out of the lower end. No oil getting sucked into the lines.. I check that because I too think it could be an issue... but no, its not an issue for me at all. I have done this on a 1954 235 and the one I run now a stock 1959 261.
If you run vac wipers, or need the vacuum for something else, then I see a problem. But if your vac is wasted because you arent using it, just try it, then if I am wrong, you are out $20. Others with more blowby in your system because your engine is getting older and more worn might have problems. This is why I mentioned putting the valve further down the line, but you know what? If there is no sealing problems, it makes ZERO difference where you put it in the line.
I get lots of emails and messages saying thanks for the tip, but the only complaint I have ever gotten was from one person with lots of miles on his engine who admits he has lots of blowby and he swears the oil mist is getting sucked into it. So I know its a possibility, so people please.. just pay the $20 and a saturday morning or whatever.. give it a try. My bet is you will be so happy you no longer have a stain below your road tube and a very happy engine. If not, tell me here, in public! Thats how sure I am you will be thrilled. MY reputation means alot to me.
