Anyone have the part number for Steering Rack Limiters?

Remove the inner tie rod cover boots. The washer is split like a spring lockwasher. It goes on the rack shaft between the inner tie rod mount and the rack housing.
 
Here's a pic of what jrichker said, and yes that is a FORD part #
Ford list them as Travel Restrictors not Rack limiters.
Rack with Restrictors.JPG

MVC-001F.JPG
 
If you are really cheap and there's no Ford dealer near you, you can make them out of PVC pipe. Not the best, but it will work for a while.