I converted more than one Ford with fully electronic speed control.
You will need at least 4 items.
This is the basic details of what my trucks needed, 96 E250 and 96 Ranger, and should be similar for yours.
Speed Control servo with proper throttle cable and bracket from van equipped with preferrably the same engine and model year so it has the proper programming.
Wrong programming and the cruise will be sluggish or real jerky. You will have a long linear connector that has a shunt for the horn circuit under the hood.
"Clock Spring" that goes behind steering wheel, you may luck out and have one with the extra trace needed for speed control, this isn't likely, but is worth checking into before spending the money. Care during install is necessary to avoid ripping the flexible circuit tape. These usually have an instruction label right on the face detailing proper installation.
SCDS[speed control deactivation switch] this is to be installed on the master cylinder. Preferred method for install is to replace the Master cylinder with the proper 3 port unit. An OEM current production switch is preferred.
Steering Wheel