1965 fj40 with I believe a 1.5f head. Webber conversation. Plugs foul with oil. Found oil is being sucked into PVC and then into intake. Has alot of vacuum happening. PVC valve is a newer one I found online. It had this terrible fitting attached to intake, one that comes in the conversation kit seems to be pipe thread and only for fuel nipple. Is there a smaller fitting that would draw less vacuum. We are stumped here. Oil really gets drawn up filler neck. It's strange help with idea please. I have a plug in the intake for now.