No idea, but the later blocks were the 0071 castings either ground & stamped or left as cast - they could have just pulled these apart, decked the face and used them again, or just tossed them in the smelter.
I know the Alpine Blue (06/24/68 invoice date) block I had was a C118 9792506 block so I have to figure my 05C built Pontiac plant car got a C118 block - which is what I have for it.
