C is a 2 wheel drive, K is a 4x4. You can have a 3.73 or a 4.10, but not both. There is a list of build codes on the glove box door. These will indicate rear end ratio, and any tow package. A search of Chevy build codes will give you a readout of exactly what your truck has.
The 4.10 is rated to pull more. I had the votex 5.7 with 4.10 in a 96 with tow pkg. It was a capable truck I couldn't get used to the high revs on a small block so I bought a 97 7.4 exact same truck just different enging. My BIL is still using the 96 with it nearing 250,000 mi. The biggest limit is the 6,000 lb rear axle which is the capacity of the tires.
