Interesting.....6 years before the platform actually appeared the groundwork was already in place,
I suppose that this would also apply to not just the Cutlass but all of the other G bodies at that time.
The automotive news show motorweek holds marathons for their older seasons on Youtube and one of the episodes they played had this spy shot of a Grand Prix prototype that I haven't seen anywhere else. I wonder if they still have the picture in their archives.