I've seen some variation on the height of the emblem. I've never seen a factory diagram that gives a dimension. I do know that the emblem should be centered above the side marker. As far as the height...move the emblem around and see where you think it looks best. New emblems are available if the original ones look bad against the new paint.
Here is a pic of the emblem centered above the side marker and placed a little higher then where I placed mine.(probably more correct then where mine is)
I placed mine with the lowest part of the "g" right where the quarter panel starts to curve outward.