Hi Guys. my car has a 8 1/4 diff in it 1978 Newport and i have a 1974 New Yorker parts car witch has a 9 1/4 diff in it. been thinking of lower the gears in the diff to 3.23 or 2.92 as i am thinking to do some mod later to the 360 in the car was looking at 9 1/4 gears. But is there a differnce in 9 1/4s diff like early and later ? some of the cover don't look the same if this right, is the pinon and ring gear not the same to. any light wood help. as living on the other side of the world wouldn't like to buy something thats not right thanks.