[JLMounce]

Later first gen F-bodies relied on a positive stop from the steering arm that would contact the lower control arm. I believe all A-bodies had that same design where the stop was built into the steering arms.

I have a box without an internal stop and also don't have steering arms with a positive stop on them. It's never been an issue for me. You can tell pretty easily when the tire contacts the frame. If you're traveling at any real rate of speed and find yourself in that situation, something has gone terribly wrong and a tire contacting a flat frame would be the least of your worries.