Power disc brake distribution block with proportioning valve. Mounts to the driver side fender apron with two nuts. Plan on testing and or rebuilding before installation. Rebuild kits available here. You'll also need hard lines and the brake warning switch, which is available new or used.
Ford part # C8ZZ-2B257.
Here’s a video to help you rebuild the distribution block so that you can corral your Cat or Pony without fearing for your life.