How Many Horses does your Posi eat?

A stock 9" compared to a stock 8.75"? No comparison...the 8.75" is stronger. Just look at the shaft size and bearings...Ford copied the 8.75" and in typical Ford fashion, they went cheap.
Ford has always tried their best to do everything cheap.
Henry Ford would do some pretty tricky stuff to get over. He used to have vendors send a part to them in a specifically made wooden box so he could reuse the wood elsewhere in the car. He was not stupid, though I think he was a bit of a prick.
Inventor of the assembly line? Hardly!