For anyone reading this later that has the same issue as me, needing a 3/4" PCV valve opening grommet but to fit into the 1.5" hole on the stock 440 valve cover (aftermarket uses 1.22"). Here is some info / I finally found a solution. There is no easy order clear single answer, and the super nice people at Wagner also did not know, although they said they get asked about it often and wished they did. An issue with current grommet manufacturers like Dorman is that the listed " OD " measurement is actually the total diameter at the top of the grommet at the top of the flap... Which is not helpful, because you need to know the OD of the part that sits down into the hole, not the flap that covers up the valve cover surface around the hole. So I bought like 15 different ones, and finally found a 2 part solution. Dorman Item # 42344 fits into the 1.5" hole, but the new hole is now 1" , not 3/4". Dorman 42339 is a multi pack of grommet plugs, and one of them fits perfectly into the outer grommet and takes the hole down to 3/4" , the Wagner valve fits great (or any 3/4" PCV). Its a very tight fit but I was told by Wagner that its better that than for to be loose. I don't love that it's two grommets. But I could not find another solution.
