Some manifolds have a cast boss that you can drill & tap (pipe threads) for the PCV valve

Upper breather hose connects to plate of air cleaner.





Upper breather connect to the manifold via the valve

Im running a gx manifold, it has one provisional port which the brake master is vented to...
thats ontop of the manifold... looks like drilling into the cast boss is the only option.
Would any pcv valve do?? If someone has a pcv and crankcase breather(the non curved large type) for sale please let me know.
Thanks again fellas!

No, not any PCV valve will do. Buy one for a Datsun A12.

interchange:
* Nissan J30 1993-1997
* Subaru 1998-2002 FORESTER 2002 IMPREZA
* any 1970s Datsun

I'd actually dissagree with that, any metallic non-return valve that fits should be fine. Nothing special about it, just a ball, spring and seat, sometimes not even a spring. It's sole purpose is to limit back flow from a back fire.

It would be best to port it to each runner to get even flow but if just to one it should work. With any luck you'll have enough adjustment in the idle airbleed to compensate for it. It's your project though, do what you want. Running a bit lean on one cylinder at idle won't really hurt, might just run a bit rough. There's relatively less flow through the pcv at wide open throttle.

So a valve off a 5-liter engine will work the same? I think not. It will work but the flow characteristics might be incorrect.

The purpose of the valve is primarily to control the flow. Small flow for small throttle openings and larger flow for larger throttle openings and is load-sensitive. For this there is a spring-loaded pintle and not just a simple anti-backfire valve. At least with Datsun's variable-flow PCV system.

Datsun's only mention of anti-backfire is the "flame arrestor" which is in the air cleaner hose (not in the hose to the PCV valve).

By that argument the 1200 one wont be right either since it's not a stock manifold, particularly if it's only connected to one runner.

I'm sure you'll figure out something that works.