When the now famous Porsche 935 came out in the 1970’s, it sported a new front design which eliminated the 911’s round headlights, thus forming a totally flat hood, or "slant nose" (or slope nose).
After market companies quickly got a hold of this design and began converting regular 911s to the slant nose form. It wasn’t until the mid 1980’s that the Porsche factory began offering the Slant Nose body option to the 911 Carrera or 930 Turbo. You could get just about every combination:
the Carrera Slant Nose, in Coupe, Targa, or Cabriolet form, or the 930S, meaning Turbo Slant Nose, which came in all three body forms as well.