Thanks for everyone's suggestions. I tried the "threaded rod" suggestion I got from Team Camaro this and it worked. By cranking on the nuts, I was able to squeeze the control arm down the 1/8 inch I needed.
Now I need a suggestion on the type grease to use on the ends of the bushings as I drive the control arm into the subframe. These are stock type rubber bushings
I would think standard grease would degrade the rubber. I know that silicone grease would be good but when I look for "silicone grease" on the auto part store websites, all I see is liquid sprays. I have also read where something like Mobile 1 synthetic grease would be good.
I just don't want to put anything on there that will hurt the rubber.