For anyone who's read this post & thought I was trying to market these things, I swear to Buddah I'm just a regular person who happens to know about them.

Sorry I'm so enthusiastic, but I'm just trying to help. Think what you want, but if you discount my post because you think I'm trying to dip into your pocket, believe me, it's your loss.

I found the Hotrodders site while doing a search for en valves.
Nobody seemed to know much about them here so I thought I'd fill you all in.
It really does eliminate blowby by routing it back thru the engine. I have first-hand experience of these things and I can tell you they WORK like a charm. If you know how pcv valves work, you'll know a brand new one only works right for about 6 months, then you start getting blow-by. This one never stops working right because it adjusts itself.

I used to work at Garden of Speedin' (sourcebooks for classic auto parts) and I called Emil (the inventor) to see if he'd advertise in the books. I didn't really know what an en valve was, so he sent me a bunch of before & after smog tests.

I bought a couple from him for my own use and my 1972 Dodge van tested way better than it needed to pass smog. It also stopped my oil leaks by creating a vacuum. It kept my oil clean too. Best money I ever spent on auto parts and takes about 15 minutes to install.

If you're doing it so you can pass smog though, change your oil, put in the valve & drive the vehicle about 200 miles before getting your smog appointment. it might run a little rough for about 75 miles till it blows all the gunk out of the exhaust system, but it'll smooth out.

Anyway, I found a guy online who's still selling them & I'm buying two for a friend's old cars that won't pass smog. misterfixit has them.