[MJN]

The hub and rotor come off as an assembly. The drive flange is held on with 6 studs and under the center dust cap is a snap ring. With the flange removed you will need a special socket to take the spindle nuts off, then the whole hub and rotor will come off the spindle. You'll have to press the wheel studs out if you want to replace the rotor and then probably replace the studs while you're at it. The spindle nut socket is the only special tool you'll need unless you're doing ball joints at the same time.
I had the same drive flanges on my '74 K20 until I switched it to a NP205 and put Spicer hubs on.
There is also a pdf file of the Dana 44 service manual located at this thread http://67-72chevytrucks.com/vboard/s...d.php?t=545416
The second page shows the drive flange, studs, snap ring, dust cover, etc. used on the 8-lug Dana 44 with external style hubs (1st design 1973-1977).
Scroll down until you get to the axles/steering section.