273 Commando or Not?

First off, the "A" stamped on the block indicates that it is a 1965 motor, and the 9-2 is the assembly date of the motor. Of course the 273 is the displacement. The casting date of 7-3-64 is just about right for the big production push for the 65 model year. On the drivers side there should be a 7 digit casting number, that would also help identify the motor.

Now, the 463 is not the rear end ratio it is the rear end code, although I don't have the 64 Production Option Code book here to decode it. I'm assuming it is the original 7 1/4 though, as the 8 3/4 wasn't available until 66 in an A body. Geof