Do what I did to cut the holes in the roof, print out the picture and measure two like spots, one on picture and the same on the car. If the spot on the picture is 5'' and it is 10'' on the car then it is 2 to 1 ratio. That means if the holes are 2" from the edge of the trunk in the picture you will need to measure 4" from the same spot on the car. Measure the holes on the picture and use the ratio to mark the holes on the trunk.
It is an A body 8 3/4 rear end. I removed the springs and replaced them with a 4 link suspension.