Rear end, driveshaft questions...

http://www.moparts.org/Tech/Archive/axle/5.html

found this chart....from what i can see it looks like about .66 of an inch...or about 5/8

in fact...i replaced the 8 1/4 in my 73 duster with a 8 3/4 and i am using the same driveshaft uncut....