One of our completed black Deluxe interior front seats sits next to the original blue standard interior bucket seat for comparison.
While our '66 hardtop's new sheetmetal is slowly finding its way to the quarter-panels and floors of our Mustang, we have plenty to do with everything we've removed to get the Mustang down to a rolling shell. Items such as the heater box, seat upholstery, gauge cluster, engine rebuild, and more can be restored and upgraded while the bodywork is being completed.
One of the first things we wanted to accomplish--mainly because we couldn't wait to see the finished product--was the reupholstering of our hardtop's seats. Not only were we going to change colors, but we also planned on upgrading the stock seats, as well as the entire interior, to the more luxurious Deluxe interior package--more commonly known as Pony interior. Just covering the original seat frames with new Pony seat buns and upholstery is a relatively simple task if you follow our suggestions here. Later, as the car progresses, we will bring you further articles on the Deluxe interior conversion process, including finding and restoring a Deluxe steering wheel, adding the woodgrain trim, and more.
When we started this project, the original goal was to restore the hardtop to pay homage to another car yours truly owned many years ago. We are still on track with that, as we gather up the correct parts to build a 289 C-code hardtop with black Deluxe interior, power steering, power drum brakes, console, and more. Stay tuned as we bring you regular how-tos and updates on our 1966 hardtop, which by the way has not been named yet.
We contacted Virginia Classic Mustang, a TMI Upholstery dealer, to help us complete our Deluxe interior conversion and provide new hardware and other Deluxe interior items that we'll be using down the road. Since we can honestly say we've never attempted this conversion, as well as the installation of new buns, we let the professionals at Mr. Autocraft in Bartow, Florida, handle the installation for us.
1 We already had the seats out of our hardtop from disassembling the car earlier. Simply remove the four retaining nuts from under the car to remove your seats. Find a suitable work area and remove the pivot arm trim from both sides, and then remove the two cotter pins to separate the seatback and base. | 
2 Beginning with the seatback, remove the seatback cover and cut away all visible hog rings that are retaining the seat cover. | 
3 Once the seat cover is free of the backside of the frame, you can roll the material around the frame to work on the front side. You might have to cut away the hog rings on the front as well, but most seat covers are so old you can simply pull them off as shown here. |
4 With the seat cover out of the way, the seat bun can be inspected. In our case (the conversion to Deluxe interior), we have to change the seat buns to accommodate the different stitch pattern. A new retaining wire is added to the standard seat to allow the retention of the Pony covers. | 
5 Once the new retaining wire is locked down with hog rings, the new Pony bun can be placed over the frame and shaped. The Pony seat cover installation begins by hog-ringing the horizontal listing wire to the new retaining wire just added. Note we had to cut the foam to get to the new wire. | 
6 Proceed next to the side, or vertical, listing wires and hog-ring them to the original standard interior retaining wires. If your old listing wires aren't long enough (they have to be cut to length for the Pony covers), then new ones can be easily made from wire coat hangers. |
7 Carefully wrap the Pony upholstery around the seatback frame, keeping the foam in place with your other hand, and then hog-ring the cover to the frameback. Check your progress as you go to work out any wrinkles. | 
8 New black seatbacks were installed, along with new seatback adjusting hardware. Don't forget new seatback mounting clips, as the old ones are usually damaged or missing. | 
9 The seat base is relatively easy, as no modifications are needed to the retaining wires or frame, but the cover is more difficult to install than the seatback. The combination of the new Pony bun and the TMI upholstery made for an extremely tight fit. Take your time and use lots of heat, such as from a hair dryer, to prevent splitting the cover. |