1970 up valve cover breathers, 1 nipple, 2 nipples, 3 nipples.

Ok, that reply of yours i pretty much can understand, but your not willing to agree that 2 nipple breathers were used on lots more engines, cars, that you not willing to admit to.
Again, personally have seen lots of vehicles, engines, with them for smog inspection, and naturally in the past on vehicles in the wrecking yards.
That's where i get them anyway.
It's not like the 1980's when they were plentiful to find, and now a days finding 40-50 year old cars in the Pick-n-Pull's are a rarity.