I just wanted to verify that the plug shown should be there. I know the engine I rebuilt doesn't currently have it. It's part #9 I think on the PET. The picture is off a spare block.

Also, does anyone know if the head vents are required for a PVC? Do the head vents intake air or relieve pressure?

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Vented heads require breather, Not certain that PVC be in the loop.

Breather ports on the heads are routed through a flashback valve then to the air cleaner, the PCV is connected directly from that port, which is open on some, closed like that one and modulated with a valve on others, eventually connected to the air cleaner.

Part #9 and 13 are for one style of PCV valve. #9 is inserted from below the flange and #13 screws down onto it to clamp the valve in place. I had this style but replaced it with a PCV valve that just has a rubber grommet that the valve forces down into.

My mistake. Misread the PET. I'm referring to the black plastic plug in my picture. This plug was used to plug the PVC access hole.

Is this plug suppose to be there? I guess it's not on the PET.

Is the plug in the green square suppose to plug the PCV access hole circled in orange or should the PCV access hole be left open?

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