PVC valves have been used like almost forever (mid to late 50's?), and this fellow moved it off of his air-box on his I-4 Dodge Shadow and got a few more HP, because the octane burns cleaner. What he calls a K&N Breather Filter is actually a Crankcase Vent Filter with a 5/8" diameter steel tube to attach the hose from the air box (air breather above the carb on mine) to the hose from the PVC valve. The fact that K&N even make this filter tells me that it's used on other engines for the same purpose. K & N's part number is 62-1060 or 62-1340. http://www.knfilters.com/search/product.aspx?Prod=62-1060 http://www.knfilters.com/search/product.aspx?Prod=62-1340 Crankcase Filter Modification http://www.karlsnet.com/mopar/crankcase.shtml Cheap way to get more MPG and a pony or two more. Here's the conundrum though. The idea of running the Crankcase fumes into the airbreather is to reduce smoke (back in the fast 50's) and today, to reduce emissions. But if your fuel is burning more efficiently (huge volumes of air mass), then the crankcase smoke generated by friction (hot oil) can't be that much. This guy may be onto something.