After much consideration, I decided to use the stock seats. They have the perfect classic style and in the right color they look great. The original color was a light/medium blue two tone that wasn't my favorite (see below). I seriously considered going with a new black interior, but frankly there are some great textures and lines in the Mustang interior that all get lost in black.
I recovered the stock seats in single color upholstery that was custom made for me. The color is a blue that's specific to '66 Mustangs only and matches the dash pad and door panels. I had the Shelby-style lap belts made in black 2" webbing with blue stitching. I seriously considered three-point belts, but these looked correct. Hopefully, I won't end up with a lap full of my teeth in a fender bender, but we'll see.
I suggest cleaning and repainting the frames, lubricating the sliders, and even replacing the padding and the burlap (at the bottom of the padding). It's the soft parts like these that fill up with mildew and create that "old car smell," which made my wife say the car gave her the creeps the first time she sat in it. :-)
. Mike used epoxy panel bond around the seams.
. (This is also a pretty good view of the 12" Baer rear disc brake kit.)