I have a 521 stroker with high volume
oil pump and FITECH throttle body EFI. I was having problems with valve cover gasket leaks, rear main drips and
oil on the underside of the opposite side breather, some other annoying drips and leaks. It was most notable if I did some hard WOT pulls while cruising around for a few hours. I put on one of these and the leaks and drips went away and the breather is clean. It made no difference on the idle or performance. I installed a small Jegs separator and it collects the mist that was sucking into the throttle body, not a lot but enough to collect and drain every 3000 miles or so. I like the fact I am not sucking that crap in the intake and the small vacuum is keeping the
oil in the engine and off the floor. valve covers are clean, no drips onto the heads or exhaust. I like it, worth the money IMO but it does not make the car run better. I played with it quit a but and can get it to suck a LOT of oil so I know it works better than a stock PCV. Adjusted properly it is as advertised. That in itself is nice as there is a lot of snake oil out there.