Try Midfifty F100 Parts, www.midfifty.com 1-800-2521956
I bought a complete Toyota setup from a salvage yard in Canada thru Ebay, but picked up the mounting bracket and pitman arm thru Midfifty...
Also No Limit Engineering and Walton Fabrication (Todd) might be able to help
All of these folks carry the whole kits and have been real nice to work with in the past. My truck is a 54 so you will have to ask if the setups they have will be alot different for you year truck.
Good Luck, Ed