Truckman,
Welcome to the Stovebolt site.
I am one of the few on this site with a 1966 C60. They are darn good trucks but thay are not without some "opportunities to be successful".
They are a 2 ton truck depending on the front and rear axle combo. Mine has a 15000lb two speed rear driven by an SM420 4 speed tranny and the 292 six cylinder. The GVW on mine is 19200.
The biggest gotcha on this model with the 15000lb rear axle is the self adjusting rear brakes. Parts are very hard to find for this "experiment gone bad" that is unique to the '66 model year. Other than the brakes, you can find all the parts on the shelf at your local Napa store. The cab is the same as the 1/2 and 3/4 ton trucks except for the front doghouse.
This site is the best source of information. There are some real knowledgeable folks that visit hear.
Buy yourself a reprinted copy of the 1963 service manual and the 1966 supplement to it.
Holler when you need help. We will all jump in when we can.
BigMac