I think you’re right about the LT1 cars having different options, at least during some years. I read about a 1993 6-Speed that came with 2.73’s stock (can you even imagine that combo?). I’m always skeptical of oddities that I’ve only heard of once before, though.
I agree 100%. I throw them on to pass the visual emissions inspection and then they come right back off. I’m finally getting around to deleting all the A.I.R. tubes and the pump when I get it fixed up.