That is probably true. The guys I know running that kind of power use a braced Ford 9 inch and run 3.89 gears with a spool and big tires. Those are 8 second door slammers running 150+ mph. A Dana 60 typically isn't a good choice in a car like that since there isn't enough space to work on the rear end. The tires are so big that the four link setup gets pushed in close to the center section. With a 9 inch you can drop the pig out and set up the gears on a bench. With a Dana 60 you are inside the car fighting with the suspension for wrench space. Do it once and you'll see why everyone uses a Ford 9 inch in the fast cars.