Vented crankcases to atmosphere where standard for decades. Actually better is claimed as less acid accumulation occurred. The change was one of the earliest components of reducing pollution.

As mentioned already. I too cannot see it impacting your pollution test. A working mechanic might give a better answer on your thread.
The exception being It might upset the mass air sensor. That is beyond my knowledge limits. Unless you look at the crankcase ventilation system as a closed loop.

Usually as I remember. The manufactures ran a tube down towards the road. Hence the name road tube was heard frequently. Another approach was the oil filler cap had holes in it. Plus some heavy steel wool inside it basically. The oil cap was actually more of a small vented container.

Oil changes where recommended at 1000 miles and some perhaps at 1500 miles. Even after cars got oil filters. Also greasing all the chassis points at the same time was normal.

Note that an Oil change is recommended before you do an emissions test because of the accumulation of unburnt fuel in old Oil. So I had previousl changed the Oil.

My 1953 chevy pickup truck has the vented cap on the valve cover and the draft tube you are speaking of as did my first car a 1954 caddilac.

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84 300D, 82 Volvo 244Gl Diesel

Would not cause any damage to engine.

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"Rudeness is a weak man's imitation of strength" - Eric Hoffer

I was not entering that it would damage the engine. But a rich mixture could clog your O2 Sensor and the Catalytic Covert with carbon.

I cleared the fault codes and took it for a 40 minute drive now there is only code 22 showing and that was the Throttle Position Sensor. Note I have had that intermittent code for about 6 years and it had always passed the emission test. I had also replaced the Throttle Position Sensor 3 times with no fix.

Will need to drive longer to see if the other fault codes return.

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84 300D, 82 Volvo 244Gl Diesel