The seats for Old Style Ford trucks are becoming very difficult to find at all, far less to find in good condition. We actually haven't seen a set in over a year, and we see thousands of vehicles. Rather than spending an eternity trying to find that perfect set, many people have turned to fabrication. The main issue was finding seats that not only fit, but didn't clash with the original design of the vehicle. Thankfully, Ford provided us with an excellent option in the 1999-2011 Ford Super Duty seats. While they are a different design, they don't look out of place. The mounting process is fairly simple as well. In addition to that the wiring is extremely simple, and there are no airbags in the seats so there's no silly "SRS AIRBAG" tag in your ~20 year old truck.
According to multiple people who have mounted these seats in, all you need to do is drill a few holes in the floor pan and through-bolt the seats. This process is simple. Align the seats in the proper position, mark the holes to be drilled, remove the seats, and drill the bolts. Use the appropriate bolt/nut/washer combination with some thread-lock, and you're finished. You can also have the nuts welded to the frame for a more professional installation.
Below are some photos of the finished product, along with some links to helpful forum posts.
Helpful Resources:
The Diesel Stop HOW-TO GUIDEPowerStroke Nation Forum Post
PowerStroke Army Forum Post
The Diesel Stop Forum Post (1)