Hey Weeds,
I forgot to add to the above that most 70s - 80s mid sized GM sporty cars have a decent rear bar. Camaros, too! You need a width so the bar comes just outside the frame. To prevent a bind, keep the arms more or less level. I got a pair of short links from O'Reillys for $4.00 each and built the mounts to suit. I used the brackets that I took off the car with new bushings for another $12.00. I think you'll find it a walk in the park!
