Found out that the rear end on my car is not original. Can someone decode this axle for me?

C BM 0309G2

He said it came out of a Nova?? I opened up the pumpkin and saw Richmond Gears with a part number of 82-071B-1. What gear ratio is this?? And are they good for a SB 350 pushing out about 350-400 HP??

Any help would be appreciated!

BM 0309G2

BM = 3.31 12 bolt non-posi axle
03 = March
09 = 9th day of Month
G = Chevrolet Gear and Axle
2= 2nd shift

Any idea what year and model this axle came from??

1970
.