To find the correct tire size for *your* specific 1971 F-250 Camper Special, you'll need to look at one of the following:
* The original owner's manual: This is the best source if you have it. It will list the recommended tire size.
* The door jamb sticker (or glovebox sticker): Many vehicles from that era had a sticker on the driver's side door jamb (or sometimes the glove box) listing tire information and other specifications.
* The tire sidewall: If you still have the original tires (unlikely!), the size is printed on the sidewall.
* Your truck's build sheet (if available): A build sheet from the factory details the specific options and components of your truck, including tire size.
* A Ford parts catalog from 1971: A Ford parts catalog for that year might list the standard and optional tire sizes for the F-250 Camper Special.
Without access to one of these sources, it's impossible to determine the exact tire size that originally came on your truck.