Emissions label

[Dale C.]

I have here sitting on my desk three emission labels, coded F, one says to adjust with the air conditioning on and two others says with the Air Conditioning off. This is for a 68 427 390hp manual trans.- pn# 3927744 with a code F. I find this difference in other publications also. Like the 68 -72 fact book, page 286, where the 68 T code calls for A/C on and CN and CR call for A/C off. So, for my car, label F, would the label say A/C on or off? Paragon label is off and Corvete Central is off also. I don't know where I got the label that says A/C on, but it does have the GM logo on the back side and the others do not.
Dale