I used a ford 9" from a 78 Lincoln Mark V. It fit perfectly with no width modifications in my '51 Chevy half ton.
I am not satisfied with the emergency brake mechanism on the stock ford calipers. In order for the brakes to keep adjustment so the parking brake will work, the brake caliper pistons have to rotate. I disassembled, cleaned, and reassembled the calipers with new rubber components. The pistons did not want to rotate freely. Now that I have run my truck for over a year, I might see if I can get the pistons to rotate now. Another alternative might be to purchase rebuilt calipers.
