Help me identify this brake drum

DoctorDiff said

That is a re-drilled A body 10" rear drum. No other drum will fit, due to the offset and center hole diameter.

Click to expand...

Do you have a source for that drum new? They are no longer available through the parts store. It is said that a front drum can be re-machined to use on the rear position, can you enlighten us on that and if it works correctly?