Tim, the b&w pic above is actually of my own 69 Bird, not an original pic.

I do have dozens of factory original pics of various 69 Birds and 69 Trans Am's, but they're always on bias-ply tires. Since most of us have white lettered radials, what I did was make my color pic b&w to look like an original to show the stance.

Lowering the back end is fairly easy. Depending on how much you want to lower it, the easiest way is using lowering blocks, available at most auto parts stores (Murray's is the cheapest). The lowering blocks include longer u-bolts (although they're usually way too long, and you will probably want to hack some of the threads off), and you can install them in an hour or two. Once you paint them black (they're natural aluminum), hardly anyone will know they're there.