I do not know anything about a house HVAC system.
Jerry,
On some USA truck 261s I have seen illustrations of the PCV tube/line being routed from the valve cover into the carburetor air cleaner.
What is your opinion on the effectiveness of that routing?
It is certainly a short line/route?
Is there a line from the valve cover into the air cleaner in/on the 1960 261 in the photo attached below?
If that is not a PCV set-up, what do you think might be the purpose of that line?
