Mounting surface to mounting surface is 62 1/4" ..Inside dimension is 55 1/4 with 3 1/2" of thickness each side (from backing plate to mounting surface). I will not use stock wheels but not sure of what to use.
Sorry my stupidity shows...I don't know what "offset" is.
The axle you have is 62-1/4" and the one you're looking at is 61". So the new diff is 1-1/4" narrower and you'll be moving the mounting surface in 5/8" on each side of the truck. Since you're changing wheels, you need to think of what you're wanting to run for wheels. For your purposes look at wheel backspacing. That tells you the measurement from the mounting surface of the wheel to the outer edge of the rim, on the back side.
As I asked before, are you fully customizing the truck or looking for a stock look? This will help determine your wheel selection, whether you want the wheels centered, to "fill out" the wheelwells, etc. Are you lowering the truck or keeping it stock height?
