Well I understand that this is an old thread but I just picked my 05 GTO and was looking for some suspension mods. Through my searching and various other forums and web searches. I happened across another members thread on here who was doing a 66 Nova project and he had a picture of the Sinjem 66 Nova/C5 rear suspension.
That led me to about 8 pictures of the project but that is all the info I have.
This was all I could find on the net. I basically had to dig through the picture info and delete stuff out of the address till I found these pictures..