I have a early 12 bolt with a code of CZ0627B
I can't find it on the axle code break downs. Does anyone know what it is?

The only "CZ" I can find is for a 68 2.73 open

I show 67 as having the same code for a 2.73. You'd have to measure the overall width of the rear to tell which year; 64-67 are suppose to be 60.5 from drum to drum and the 68-72 are 62.5.

Dale