There used to be a kit for the Pinto, but not for many years now as far as I know. Your best bet would be a universal kit for the rear frame.
Since you will be doing the above, I'd suggest going with a 4 link suspension since you can get the mounts for those as part of the frame rail kit.
Also I would seriously suggest making subframe connectors to go from the rear to the front. It sounds like that shouldn't be a problem for you to do. There are several different ones here on the forum if you do a search. But for you it will be pretty easy to just run them from the new rear frame rails to the front.
Can't help with tire size, but I know there are people here who have done it. Hopefully they will speak up.
Welcome to the site. Pictures are pretty much a requirement.
Russ