oldsub, if ya want a duelly, then get one. I can't help you out on what one you need to fit your truck. Take a tape to your fender wells and start looking for a set up that will fit.
The coil spring set up on your 72 is not the problem. There has to be enough weight to take advantage of whatever the tire footprint is. With a half ton, when you get enough weight for good traction on snow, you may be over loading the suspension. Then handling suffers.
Any truck/car can suffer from loss of traction. A lightly loaded duelly will suffer on slick surfaces. But a single tire set up can suffer just as bad too. A vehicle (single or duelly) that handles snow well with factory size tires on it can be like a hog on ice with wide tires installed. Deully tracking in some snow conditions might be a problem. I have always found that the duel axle was not loaded heavy enough when that was happening.
Having more tires on the ground is not always an advantage when breaking. Again, if there isn't enough weight to take advantage of the tires footprint, they will skid sooner than a single setup.
The duelly advantage is in safety. If a tire blows, on what should be the axle that is carrying the most weight when loaded, the other tire should help with vehicle handling. Hopefully long enough to slow to a speed that allows sure control. And a duel setup will allow you to move the vehicle out of traffic, Maybe even to continue on to where service is avialable.
Single, duelly, half ton, 3/4 ton, 1 ton, whatever, every set up has it's advantages and disadvantages. Go with what "you" want and make it work for you the best you can. Good luck. Mike
