I think a saw a thread a while ago saying that the thikness of the pinion of the 9" is the same as the 7.5" thats were I got it that they are the same... any way they break as the guy who made it here in Malta broke two ( using it on the strip) and now he have the bmw with no prob...I think even in the touring car they used to break and than switched to jag diff...This I read from a Ford magazine when they made a story about Zoo motorsport...always if my memory serves me right ( it doesn't a lot )