I picked up a set at my local hardware store........usually if you bring the header stud with you the employees can hook you up with what you need. You might want to pick up some jamb nuts as well if you dont want to mess with loctite, but that's totally your call. Hope this helps!
i just got a bolt and put it up through the h pipe when one of mine broke... 3/8or 7/16 corse thread possibly... i dont remember... i do remember ford wants like $11 each...