Venting for Fuel Injection Swap

I cannot speak for what is differing terminology. A FACTORY proper cap is not an operational vent. "It might be" that some books call them that. My recollection is that "back in the day" we would look it up, get the cap and if "questionable" would just LOOK at the darn thing AND THEN (LMAO) see if you can blow through the new cap LOL

Any of the PV caps I remember, you can tell by looking, "that is what they are"