10-bolts are 7.625", a 12-bolt is 8.625", and a Ford 9" is 9". But all of them handle torque the same way because they are C-Clip axles. An S60 is 9.75" and handles torque differently because its a non-C-Clip axle. Look it up on TGO. TGO is a far better source for tech than LS1tech. Also, an S60 is the cheapest aftermarket rear for our cars and its also the strongest.
http://www.spohn.net/shop/1982-1992...trange-Engineering-Dana-60-Rear-Complete.html
That is Strange's own product description too. They also happen to build 12-bolt and 9" rears so I think they would know.