[blucar]

You have stated that you just want to get working lights for your truck, that be the case avoid original reflector/bulb lights, you will spend a lot of money for nothing. As I stated earlier go with the Guide style #682 sealed beams, they have the park light on top. The 682's come in two styles, bottom mount and side mount, you will need bottom mount.
If you are going to leave the truck 6v, wire a GM type relay into the system, then the switch will only activate the relay, which in turn will turn the lights on. The lights will be very bright. Eliminating the original Ford switch in favor of a modern pull switch mounted in the dash would also be a good idea.
A good pair of 682's will set you back about $175/400. on ebay.. Go onto eBay, enter Guide 682 c lights, pages of them will come up.