Fords of that era have quite a common issue with dry outer tie rod ends and ball joints. To troubleshoot these, I use either a needle greaser with my grease gun or a pin pick through the boot and spray white lithium grease. I try to narrow down at least which side the noise is coming from and if it seems more like ball joint or tie rod end, then lube one at a time inside the boot. If the one I choose to lubricate makes no difference, then I move to another joint, etc. until I find the one that makes a change. From my experience, you'll notice a change VERY quickly. Also, the white lithium grease "fix" will only be a temporary one.
-Rod