Not to bore anyone here but to add another consideration...if you have a stock front end/suspension, the best way to preserve the steering geometry designed into it will be to match as closely as possible the width and height of the wheels/tires originally used plus the wheel offset (if your new wheel deviates from centerline orientation). There were 2 types of 600/16 tires: car and truck. The specs for the truck tires were: 28.8" diameter and 6.8" wide. The closest thing you'll find in a 16 inch radial is 205/75r16 and the specs on it will be 28.1" with a width of 8.1"...which ought to be okay although the extra width could work against you a bit. The diameter and width aren't important on your rear end but they are important on your front end. You don't want to wreck your scrub radius and that can happen easily...the scrub radius being figured by measuring the point at which your steering axis line hits the ground and figuring the distance between that and the center of your tire. In the AD trucks (all weights and sizes of them) this measurement was called the King Pin Inclination Angle and it was 7 degrees 10 minutes plus/minus 1 degree. Only an axle shop will be able to adjust this because it is permanently set into your axle. If you draw a line right through your king pin and down to the ground you'll discover it was designed to produce a positive scrub radius with stock wheels and tires (this is important). If the line had hit dead center your scrub radius would be zero. Some think that's okay, but it isn't. If it hits closer toward your frame your scrub radius is positive and if it hits on the outside of the center point (heading away from your wheel) your scrub radius is negative. All measurements of your new wheel/tire (diameter, width of tire and offset of wheel) affect this. Looking only at diameter, the further you move away from 28.8" the more negative your scrub radius will be. The more you move toward a number smaller than 28.8" the more positive your scrub radius will be. Wherever your king pin inclination angle hits the ground will be your pivot point. That's unavoidable. A positive scrub radius will make your steering easier...up to a specific point, anyway. A negative radius will make your steering harder...and this little understood factor can have a big effect on things. My experience has been the more negative your scrub radius becomes the difficulty of steering increases exponentially.
Here is what the AD Shop Manual says:
"The purpose of kingpin inclination is to keep the wheel spindles pointed outward in line with the axle to decrease frictional resistance of the tires against the road when turning right or left which results in easier steering." And their figure 14 shows an obvious positive scrub radius.
Just a thought some folks don't consider. Many of my friends have used wheels and tires which change their scrub radius and have wondered why it is so difficult to drive around in town after the change. This is one of those things which will affect that. Good luck! I'd keep this in mind when changing wheels/tires.
