Yes makes sense that it should open with vac applied. I will make sure I my looking at/testing it properly to be sure it's the wrong PCV. Looks like I have 61/62 ,either car or truck,
RPO242
In my earlier info I implied that they first came out in 1961. Actually that was the year GM provided them on ALL California cars and then nationally in 1962. According to unnamed historians. I got that RPO number from a copy of a "parts book" reprint 1973. So looks like PCV (or PVV as Bill and TC's info indicates) was possibly an option way back, at least in 61/62 it was RPO242.
If I put the PCV I have on the opposite end of the system (screwed into manifold instead of tube) it would reverse it's closure action. That's not where it was when I got the truck. It's not where they are placed on all info I've seen. Then I will put on a big old air breathing oil cap. Am I getting there? Am I normal?
Anybody have a twist on vent cap part number, that fits a 235 cover? can only find clip on type.
