Check out my pictures on the link below.
I have installed disc brakes on my 2 ton.
It can be done, it is not simple, but well worth the effort.
Basically it involves finding a newer front axle like from a step van with the same bolt pattern, 5 lug front and 10 lug rear is my guess as to what you have, then narrow the axle to make the tires fit in the fenders.
Grigg
