only the rear is wider on '86 and newer toyotas (truck and 4runners) the fronts went to IFS.
If you want to widen the front you can byuy a kit from front range off road and I think Sky MFG as well. I did a hombrew version and gained 1.5" each side. or you could just get wheel spacers.
Get longfields or smurfields and don't worry about the birfs again. I was running 37" tires, 4.3 v6 and 6-:1 gearing and once I got smurfs never broke one. Before it was pretty much break one every trip.
You can get stock gearing in toyotas to around 4.37 in the '79's for still pretty cheap.
I woiuld go toyotas as a diff swap in a heart beat.