Casey,

Yep he is right, the pn really is 5209 for the 2".
Brain fart
They have one slip tube that wraps around the torsion bar, and they do have a 3.5" collector ring for a bolt-on exhaust.

The 1&7/8 also work fine, but most of them need 2 small dings so the plug socket will go on. A few folks have had good luck not dinging and instead using an open end wrench for spark plugs, or grinding the socket to shorten it, but I never tried that.

Besides budget, the only question that is left is which one to use? IMO the 1&7/8 are fine for a street car. Mine ran low 11's with 1&7/8 through the exhaust, and picked up nothing with open headers. If it weren't for the never ending quest for a 10 second run, I wouldn't bother with the 2".